before anyone comes in here and says it, I will
this isn't a hobby where you can just throw a bunch of shiot together and throw it in yoru car and be done with it....it requires a bunch of research and a bit more time....
take it easy and look around....there are threads pertaining to your questions
there is no motorized vga touch screen on the market....though there is talk of one, I wont hold my breath (and I'm sure there are a bunch of others who will agree with me here) till I see it..
shuttle is too simple for my taste, but it works great for some people, here, would be an excelent time to go get a bag of popcorn and a coke and sit and read....because only you will be able to make that decision for yourself on something like where to place the computer and which ones to go with.
on power....there is an ENTIRE forum dedicated to power....go read it, where that popcorn and coke come in handy again
the reason those FAQs don't tie anything up, as you put it, is that there is no perfect psu for EVERYONE out there, again, read and do some research, you will have to part together what you want and what will work for you.
On the startup tips.....that might just get you hard core flamed in a few minutes here....
there are like a BAGILLION threads and a lot of products out there that cover this....JUST READ and ye shall find the answers
on a fairly tight budget! who isn't?