Thanks Fred. Very logical explanation! I don't see myself in need of other electrical devices than aux lights and GPS at this point. Frame grounding seems like simple to do.
The battery neg cable attaches to the lower right corner of the engine (at least on the Gen I), you can see the connection behind the #4 exhaust header. The battery neg post and unpainted parts of the engine are the best grounding points. The main frame that the engine is well bolted to is just about as good. By the time you get to the front and rear sub frames the grounding is better for power accessories and not communication or entertainment gizmos. The front cowling area is probable the least preferable grounding point. (As others have said in previous posts.)
You can tap the battery with brass plates that accept spade connectors, I found the one I use at a local Auto Zone parts place but they can be found on eBay and even Amazon. I would expect you could solder to the plates before installing them with the battery bolt. I did have to slightly bend down a couple of tabs for best fit.
WirthCo 30700 Frame Ground Tap and Performance Plus makes the more common taps.