Things haven't been so hot - I spent most of last weekend trying two approaches to the watchdog issue; implementing Stskeep's n900-support package which uses DSME to ping the watchdogs, and I've tried Jebba's approach which uses the watchdog package to directly ping the watchdogs - both did not work

Yes and no; Yes, in that would prevent the hw watchdog from rebooting the device, and No because Ubuntu seems to also be shutting it's self down later on in the boot process due an unknown issue that i need to look into.

Also, in my opinion putting the device in R&D mode just to boot another OS seems like bad practice, is unnecessary, and can be quite unsafe - especially for an inexperienced user who just wants to try out another os. When playing with R&D mode your playing with _very_low_level_ components of the device, and messing up these sensitive components could turn your device into a permanent brick. (i permanently bricked my N800 while experimenting with these components - accidentally wiped both the x-loader and nolo (1st and 2nd bootloader) turning it into a paperweight) Some people have also occasionally reported strange bugs while booted with R&D mode. Enabling R&D mode on the device really isn't recommended unless absolutely necessary.

One of my goals with the projects that i do is to make things as non-invasive, safe, and as simple to setup as i can so everyone can try it out.