I don't know of any list of the differences, though I agree it would be handy.
I don't map for SP, just MP, so I can only speak to the things I know don't exist in MP.
I know you can't toggle lights in MP (and you'll never be able to), there are no weather effects, no ladders, and you can't toggle doors or func_trains. I know of no "workarounds" for those things.
I wasn't aware of any shader differences between the two, that's interesting. Do you have the SP settings doing a fullbright compile vs. a regular for MP? Or maybe SP has a default ambient built in.
My only suggestion is to write a mod, or find someone that can. That's the only real way of getting the most of the code.
My brother is my coder. He's given me more amazing stuff to do in maps that I could easily count, including ladders, toggle door and trains, rotating trains, timers, model specific triggers, and so on.
So it can be done, it just can't really be done my a mapper alone.