So I'm basically in the same boat as you. The standard shader would work perfectly, however there are a few things that Id like to modify to suit our exact needs(using a different UV set for AO, using alpha for transparency or not, etc) Id like to have a working base that I could modify and stop wasting time trying to figure this puzzle out. Id love to take the time to poke around this, but unfortunately time is short these days and online resources are scarce. On a side note I have a problem with the shader that Ive managed to make so far, it seems like it multiplies the specular color, white in this case, with the albedo, resulting in a overly white chrome look-a-like. Every model I use this shader on is reflecting whitish specular instead of using the spec map purely as a, well, specular(rgb)gloss(a) map. Any ideas on how I can fix this, as this doesn't happen in the default standard shader provided with unity.