I was having trouble formulating my thoughts on this until I read this sentence. Please, please don't. Sticking LEDs onto cobbled-together, unplanned and semi-thoughtless crud does not make it look better. At all. Also, MDF is a very decent material - sturdy, easy to work with, relatively inert. If you want to make it look better, paint it or cover it with a vinyl wrap. Acrylic is brittle, scratches easily, and doesn't carry loads well.
What I would do: plan this out more. Where are you going to add fans? How is air supposed to flow? How are you keeping dust out? Where are your cables going to connect?
Your current layout has essentially zero airflow, and no natural place for fans to be added. It's open-air, so hot air will eventually leave, but that adds dust as a problem. Your PSU is taking in air from the (quite small) gap between it and the board above, and its exit is partially blocked by the cardboard rails. It will also (partially) be taking in hot air from the CPU cooler, which (due to no airflow) will also be recycling its own heated air). The connectors on the laptop motherboard and the desktop motherboard are on different sides of the case.
Also, as you're using MDF(?) plates, that means your motherboard mounting points are ungrounded. I'd do something about that, just to be sure. Perhaps wire them to the PSU casing? Be careful you don't short anything out, of course.
Also, you mentioned four computers, so far we've only seen to. Are the remaining two desktops?
Are your base plates held in place in any way? Or would, say, walking by and stumbling into the case cause them to flop around and kill your hardware?
I would at the very least add a 120mm fan blowing air across each board, and make sure the PSUs have clear intake pathways (drilling a properly placed hole in the board above should fix that).