--Was able to recompile pwm.ko in /omap3-pwm and get 17K file using command 'make ARCH=arm CROSS_COMPILE= -C /lib/modules/3.5.0-2-linaro-omap/build M=/ modules' (note blank (NO QUOTES) after CROSS_COMPILE=).  Also works with ARCH=armv7l (symlinked to arm).  Running modinfo on the new file shows identical output to the (working) regular pwm.ko module located in /root/build/linux-omap-3.5/drivers/omap3-pwm/, so it seems reasonable to assume that it would work the same way.  Also able to recompile gpio-event-drv.ko (from /root/build/linux-omap-3.5/drivers/gpio-event/module) the same way in a temp directory, with file size and modinfo matching original.
--After editing Makefile in /root/build/linux-omap-3.5/drivers/input/misc to add 'obj-m := rotary_encoder.o' on its own line, was able to compile rotary encoder module using command 'make ARCH=arm CROSS_COMPILE= -C /lib/modules/3.5.0-2-linaro-omap/build M=/ modules'.  After linking it to modules directory with 'ln -s //rotary_encoder.ko /lib/modules/3.5.0-2-linaro-omap/kernel/drivers/input/rotary_encoder.ko' and running 'depmod -a', was able to check modinfo and see a vermagic line that matched the working modules.  Was able to load module with 'modprobe rotary_encoder', verify it was loaded with lsmod, and remove it with 'modprobe -r rotary_encoder'.  It appears that I have figured out the correct commands to make a loadable module.  Now I need to figure out how to modify and/or configure this module to monitor the gpio pins that I'm using for the encoders.
--Taking rover down to machine shop for mounting of microphone and speakers.  Will see if it is possible to mount speakers on the underside of the rover.