These are the materials I advise be used to reproduce my DDR Platform:

Building materials (stuff you can get at the mega-hardware store):

WOOD*

1 - 36** X 36 X .75  particle board (base)
3 - 11 X 11 X 15/8  particle board (blocks made from three 5/8 squares)
12 - 11 X 2 X 1.5  wood (sides of each button - from standard 2-by-fours)
6 - 5 X 2.5 X 1.5  wood (switch bases - also from 2-by-fours)
3 - 36 X 15/8 X 1 wood (side and rear edges)
1 - 36 X 15/8 X 1.5 wood (front edge)
1 - 2 X 6 X .5 scrap (for mounting PSX controller - unnecessary, but recommended)

For exact wood projects, using solid wood is not a good idea because it warps with moisture.
I used some here, even for important parts, because it was a first attempt. It clearly
works, but I suggest using particle board whenever possible. Medium Density Fiberboard (MDF)
is actually the best option because it is very strong and smooth. For my next platform, I
intend on making the entire thing out of MDF. I have only found MDF in 3/4 X 48 X 96 sheets
so some parts will be made from MDF glued to itself as was necessary for the inactive blocks
with the current model.

**Any measurement listed as 36 inches is an approximation. These need to be trimmed to fit
after everything else is in place. Starting with an oversized board is also a good idea.
There really should be a lot of accuracy with this project, though, so if I had the
platform near me right now, I would make exact measurements of these 36 inch pieces. They
are all definitely between 35 and 36 inches, though.

Sheet Metal

2 - 24 X 48  26-guage steel (use plate or stainless, whatever you want to pay for)
You can always buy larger sheets... a single 36 X 48 sheet would have done the job nicely.
If you're buying sheet metal, you should understand a few things about it and feel free
to get whatever you want to work with... just make sure it won't rust.

Plexiglass

1 - 24 X 48 X .25 Lucite (found this at Lowe's in Indiana, but not at Home Depot in
New Hampshire where I also looked. If they don't have it at your local megastore, either
ask them to order it for you or go to a glass replacement place and ask them about it.)

I don't know much about plexiglass. I know this is a key component of the platform. Getting
.250 thickness is extremely important. The strength of the plexi is what provides the
spring in the platform buttons. Cut into 11 inch squares, you shouldn't be able to bend it
with your hands very easily, but it'll bend just fine underneath your weight.

Screws

Lots... will update with exactly which ones I used.


Non-Building Materials:

24 - Cherry microswitches (I used the 10 amp ones, anything else should work too)
2 - Mini pushbuttons (one blue, one red, or whatever colors you want)
24 - Corner brackets (not easy to find, but I can supply them)
1* - Cheapass PSX controller

*The cheaper, the better. Funcoland has some exceptionally low-quality ones from various
no-name for about $3.50. You want to avoid controllers with special features like autofire
and slow-motion. The coolest ones to get have none of these features and may even have a
red LED in them that is activated any time a button is pressed. This is great for testing
your soldering without needing to watch how a PSX game reacts. I know crappy Kodiak brand
controllers have included this LED as have other cheapest-of-the-cheapass controllers - 
all bought from Funcoland. Of course, ANY controller that works in a PSX will work for this
project, so don't go out of your way looking for anything but the cheapest.