[Motorola Droid RAZR] sevenup30:
repo sync take very long time, if you want to make it shorter, you can edit your local_manifest.xml to match only with the device you want to build.

it looks like (for umts_spyder):

<?xml version="1.0" encoding="UTF-8"?>
<manifest>

<remote name="omapzoom"
fetch="git://git.omapzoom.org/" />

<!-- CM removals -->
<!-- <remove-project name="CyanogenMod/android_bionic" /> -->
<remove-project name="CyanogenMod/android_build" />
<remove-project name="CyanogenMod/android_development" />
<remove-project name="CyanogenMod/android_frameworks_av" />
<remove-project name="CyanogenMod/android_frameworks_base" />
<remove-project name="CyanogenMod/android_frameworks_native" />
<remove-project name="CyanogenMod/android_hardware_libhardware" />
<remove-project name="CyanogenMod/android_hardware_libhardware_legacy" />
<remove-project name="CyanogenMod/android_hardware_ril" />
<remove-project name="CyanogenMod/android_hardware_ti_omap4xxx" />
<remove-project name="CyanogenMod/android_hardware_ti_wlan" />
<remove-project name="CyanogenMod/android_hardware_ti_wpan" />
<remove-project name="CyanogenMod/android_hardware_qcom_media" />
<remove-project name="CyanogenMod/android_packages_apps_Bluetooth" />
<remove-project name="CyanogenMod/android_packages_apps_Contacts" />
<remove-project name="CyanogenMod/android_packages_apps_Mms" />
<remove-project name="CyanogenMod/android_packages_apps_Phone" />
<remove-project name="CyanogenMod/android_packages_apps_Settings" />
<remove-project name="CyanogenMod/android_packages_apps_Stk" />
<remove-project name="CyanogenMod/android_packages_apps_VoiceDialer" />
<remove-project name="CyanogenMod/android_packages_apps_CMUpdater" />
<remove-project name="CyanogenMod/android_packages_providers_ContactsProvider" />
<remove-project name="CyanogenMod/android_packages_providers_DrmProvider" />
<remove-project name="CyanogenMod/android_packages_providers_TelephonyProvider" />
<remove-project name="CyanogenMod/android_system_core" />

<!-- CM replacements -->
<project path="build" name="STS-Dev-Team/android_build" >
<copyfile src="core/root.mk" dest="Makefile" />
</project>
<!-- <project path="bionic" name="STS-Dev-Team/android_bionic" /> -->
<project path="development" name="STS-Dev-Team/android_development" />
<project path="frameworks/av" name="STS-Dev-Team/android_frameworks_av" />
<project path="frameworks/base" name="STS-Dev-Team/android_frameworks_base" revision="jellybean-3way" />
<project path="frameworks/native" name="STS-Dev-Team/android_frameworks_native" />
<project path="hardware/libhardware" name="STS-Dev-Team/android_hardware_libhardware" />
<project path="hardware/libhardware_legacy" name="STS-Dev-Team/android_hardware_libhardware_legacy" />
<project path="hardware/ril" name="STS-Dev-Team/android_hardware_ril" />
<project path="hardware/ti/omap4xxx" name="STS-Dev-Team/android_hardware_ti_omap4xxx" revision="jellybean-stock" />
<project path="hardware/ti/wpan" name="Hashcode/android_hardware_ti_wpan" revision="jellybean" />
<project path="packages/apps/Bluetooth" name="STS-Dev-Team/android_packages_apps_Bluetooth" />
<project path="packages/apps/Contacts" name="STS-Dev-Team/android_packages_apps_Contacts" />
<project path="packages/apps/Mms" name="STS-Dev-Team/android_packages_apps_Mms" />
<project path="packages/apps/Phone" name="STS-Dev-Team/android_packages_apps_Phone" />
<project path="packages/apps/Settings" name="STS-Dev-Team/android_packages_apps_Settings" />
<project path="packages/apps/Stk" name="STS-Dev-Team/android_packages_apps_Stk" />
<project path="packages/apps/VoiceDialer" name="STS-Dev-Team/android_packages_apps_VoiceDialer" />
<project path="packages/providers/ContactsProvider" name="STS-Dev-Team/android_packages_providers_ContactsProvider" />
<project path="packages/providers/DrmProvider" name="STS-Dev-Team/android_packages_providers_DrmProvider" />
<project path="packages/providers/TelephonyProvider" name="STS-Dev-Team/android_packages_providers_TelephonyProvider" />
<project path="system/core" name="STS-Dev-Team/android_system_core" />

[COLOR="Red"] <!-- local devices -->
<project path="device/motorola/common" name="STS-Dev-Team/android_device_motorola_common" revision="jb" />
<project path="device/motorola/umts_spyder" name="STS-Dev-Team/android_device_motorola_umts_spyder" revision="jb" />

<!-- local vendor -->
<project path="vendor/motorola/common" name="STS-Dev-Team/android_vendor_motorola_common" revision="jb" />
<project path="vendor/motorola/umts_spyder" name="STS-Dev-Team/android_vendor_motorola_umts_spyder" revision="master" />[/COLOR]

<!-- local misc -->
<project path="frameworks/opt/telephony" name="STS-Dev-Team/android_frameworks_opt_telephony" revision="jellybean"/>
<project path="packages/apps/FileManager" name="STS-Dev-Team/android_packages_apps_FileManager" revision="ics" />
<project path="kernel/motorola/omap4_xt912" name="STS-Dev-Team/kernel_omap4_xt912" revision="master" />
<project path="prebuilt/linux-x86/toolchain/arm-eabi-4.7" name="STS-Dev-Team/arm-eabi-4.7" revision="master" />

<!-- TI addons -->
<project path="device/ti/common-open" name="device/ti/common-open" remote="omapzoom" revision="jb-release" />
<project path="device/ti/proprietary-open" name="device/ti/proprietary-open" remote="omapzoom" revision="jb-release" />
<project path="external/bltsville" name="platform/external/bltsville" remote="omapzoom" revision="master"/>
<project path="external/crda" name="platform/external/crda" remote="omapzoom" revision="p-ics-mr0" />
<project path="external/wpa_supplicant_8_ti" name="platform/external/wpa_supplicant_8_ti" remote="omapzoom" revision="jb-release" />
<project path="frameworks/opt/mms" name="platform/frameworks/opt/mms" remote="omapzoom" revision="master"/>
<!-- <project path="hardware/ti/domx" name="platform/hardware/ti/domx" remote="omapzoom" revision="jb-release" /> -->
<project path="hardware/ti/wlan" name="platform/hardware/ti/wlan" remote="omapzoom" revision="p-jb-release" />
<project path="packages/apps/OMAPCamera" name="platform/packages/apps/OMAPCamera" remote="omapzoom" revision="jb-release" />

<project path="packages/apps/otaupdater" name="STS-Dev-Team/ota-update-centre" revision="noicon" />

</manifest>

just keep "common" & "umts_spyder" in local device & local vendor, then you wont have whole source for all devices supported.