First off, I have never had to install a stand alone boost gauge and curious what they work off of? IE, 5V voltage variance, resistance? has anyone looked into using data from the MAP sensor on the manifold to get boost data?

Mine works off of a little hose to my intake. I imagine someone makes an electronic one but the only ones I have ever used were mechanical.

The map sensor gives the computer a voltage reading and yes you can monitor it electronically. A scanner does this, it is the easiest way. Back before scanners were affordable for independant shops it was common for mechanics to use a multimeter to test map sensors. It can be done with the sensors on our trucks this way as well but a manual conversion from voltage to barometric pressure is required.

There is some kinda hoohicky (Real scientific, huh?) you can hook to OBDII and watch parameters like MPG, RPM, etc. in a display format. It could be modified to read boost I'd guess if OBDII displays this (Which I'm not sure it does)

Guess that didn't help at all. :D