[Nexus 6 Android Development] pdfruth:
I will try without V4A (oh man, I hope that's not it... I gotta have my V4A. V4A is killer-awesome).

In the meantime... I pulled 'adb logcat' output.

I see this at about the time of the last reboot;

10-28 19:42:29.130 6724 6948 F libc : Fatal signal 11 (SIGSEGV), code 2 (SEGV_ACCERR), fault addr 0xa4d49698 in tid 6948 (Thread-7), pid 6724 (system_server)
10-28 19:43:11.437 20370 20370 F DEBUG : *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
10-28 19:43:11.438 20370 20370 F DEBUG : Build fingerprint: 'google/shamu/shamu:7.1.1/N6F27M/4299435:user/release-keys'
10-28 19:43:11.438 20370 20370 F DEBUG : Revision: '0'
10-28 19:43:11.438 20370 20370 F DEBUG : ABI: 'arm'
10-28 19:43:11.438 20370 20370 F DEBUG : pid: 6724, tid: 6948, name: Thread-7 >>> system_server <<<
10-28 19:43:11.438 20370 20370 F DEBUG : signal 11 (SIGSEGV), code 2 (SEGV_ACCERR), fault addr 0xa4d49698
10-28 19:43:11.438 20370 20370 F DEBUG : r0 a4d48700 r1 a4d48800 r2 a4d48900 r3 a4d49698
10-28 19:43:11.438 20370 20370 F DEBUG : r4 86ce0570 r5 83a10094 r6 93784924 r7 83a736c0
10-28 19:43:11.438 20370 20370 F DEBUG : r8 83999d00 r9 83999d00 r10 83999d0f r11 83999d0f
10-28 19:43:11.438 20370 20370 F DEBUG : ip 83a72f9c sp 937848d0 lr 839cc045 pc a4d49698
10-28 19:43:11.493 20370 20370 F DEBUG :
10-28 19:43:11.493 20370 20370 F DEBUG : backtrace:
10-28 19:43:11.493 20370 20370 F DEBUG : #00 pc 00049698 [anon:libc_malloc:a4d00000]
10-28 19:43:11.493 20370 20370 F DEBUG : #01 pc 00008043 /system/lib/libloc_eng.so (LocEngReportXtraServer::proc() const+318)
10-28 19:43:11.493 20370 20370 F DEBUG : #02 pc 000039fd /system/lib/libloc_core.so (loc_core::MsgTask::loopMain(void*)+84)
10-28 19:43:11.493 20370 20370 F DEBUG : #03 pc 0000dc33 /system/vendor/lib/hw/android.hardware.gnss@1.0-impl.so (threadFunc(void*)+6)
10-28 19:43:11.493 20370 20370 F DEBUG : #04 pc 00063d03 /system/lib/libc.so (__pthread_start(void*)+22)
10-28 19:43:11.493 20370 20370 F DEBUG : #05 pc 0001df85 /system/lib/libc.so (__start_thread+32)
10-28 19:45:20.335 6724 6800 I PowerManagerService: Waking up from sleep (uid=1000 reason=android.policy:POWER)...
10-28 19:45:20.335 6724 6724 W UsageStatsService: Event reported without a package name
10-28 19:45:20.344 6724 6800 D WindowManager: powerPress: eventTime=28542812 interactive=true count=1 beganFromNonInteractive=true mShortPressOnPowerBehavior=1
10-28 19:45:20.364 6724 6748 I DisplayPowerController: Blocking screen on until initial contents have been drawn.
10-28 19:45:20.396 6724 6746 I DisplayManagerService: Display device changed state: "Built-in Screen", ON
10-28 19:45:20.519 6599 6599 W wificond: Failed to get NL80211_ATTR_EXT_FEATURES
10-28 19:45:20.526 6599 6599 W wificond: Failed to get NL80211_ATTR_EXT_FEATURES
10-28 19:45:20.535 6724 6748 I DisplayPowerController: Unblocked screen on after 170 ms
10-28 19:45:20.701 6724 6724 V SettingsProvider: Notifying for 0: content://settings/system/screen_brightness
10-28 19:45:20.708 6724 6748 W PowerManagerService: Screen on took 612 ms
10-28 19:45:22.591 6940 6940 E AndroidRuntime: FATAL EXCEPTION: main
10-28 19:45:22.591 6940 6940 E AndroidRuntime: Process: com.android.phone, PID: 6940
10-28 19:45:22.591 6940 6940 E AndroidRuntime: DeadSystemException: The system died; earlier logs will point to the root cause
10-28 19:45:23.692 20395 20395 I wificond: wificond is starting up...