I just ordered the one above and will assign a shutdown button/combo.
With lots of younger kids who 1) just hit switches randomly because it's a switch that needs to be flipped and 2) will vindictively do things like power off the game to avoid losing, was more of a personal goal to make this work. Anyways, the strip above has a software API that tells the strip to turn on when the laptop is powering up. Same when it's powering down. I have 5 extra white buttons, so plugged it in and assigned it to shut down the system and will put it in an inconspicuous place - likely out of reach of younger kids.
Rebuilt the machine with win7sp1 pro, stripped it down using the guide here and setup attractmode. Only going to use mame games for now and I do see that attractmode supports servosticks and ledblinky and other things like that, plus simple and not as bloated as hyperspin.
Bought the soundsystem last night. Went with a $20 18x2+36x1 2.1 DIY amp.

has sub, treble and master volume controls that should be easy to mount and place, plus not have to worry about generating a lot of heat. Pyle in-wall 6.25" full range speakers will be placed up high. I earmarked a pyle 6" sub, but haven't got it yet because I want to see how good these in-wall speakers work before I built that out.
Started cutting out a new CP last night and printing out the CP images mentioned earlier. Will use those to scale to build it out and get the trackball setup. Should have that done tonight.
Once the sound is in place, will get some laminate and tmolding and start the finishing work.