Built the pad platforms (games)
I ended up doing something which is (IMO) far superior to what ddrfreak recommends. This is how I built the second one; the first one took a bit longer because I had to figure out the process (the second one went really quickly).
- Prepared (i.e. cleaned off) a 38"x40" plank of particle board
- Laid a dance mat on it in the middle and marked 10 holes for drilling about 1" from the edge (one on each corner, two on the top and bottom edges, and one on each side)
- Removed the mat, drilled the holes with 1/4" diameter, and cleaned the board again
- Laid the mat down, and taped down the left and right edges securely with clear packing tape
- Laid clean window insulation plastic on top
- Used a hair dryer to warm up the window insulation to make it stretchy and soft
- Affixed the corners of the insulation plastic with a bolt, washer, and nut, keeping it taut
- Affixed the other screwholes, again keeping the plastic taut
- Cut a notch in the window insulation plastic for the cord
- Folded the excess insulation plastic around the edges of the particle board, and used packing tape to affix it (making the corners nice and safe)

I took some other pictures but they didn't come out too well. I need a decent digital camera.
Next step is to add some sort of registration bumps. Delphine suggested using packing tape to hold down the zip cord. But it would seem that I don't currently have any zip cord which isn't in use, or at least if I do I can't find it. The main thing is I just want to tell when my feet are getting off-center, which is very easy to do especially in long series of complex steps where you don't have a chance to look at your feet while playing. Unless that's supposed to be part of the skill (being able to track the steps while watching your feet)...
Of course, if you're really heavily into this stuff, you can always build your own arcade-style pads, which looks like it'd take several days' worth of planning and construction, not to mention a lot of materials costs. I think I'll stick to the $20/pair ones and my cheap platform. :D
(update) I carefully taped down zip cord (aka lampshade cord, or "the cheap-ass speaker wire from Radio Shack") between the rows and columns of buttons in order to provide registration marks (which greatly improved my accuracy, though I still have to occasionally look down to see where my feet are so it's not totally "cheating"). However, this step makes pad replacement that much more difficult, since it makes for more tape which has to be removed before a faulty pad can be pulled out. Oh well.
Comments
Salaam
iMan: Okay.
Magenta, this suggests you're one of those really annoying people who seems to just get on and do things without any kind of procrastination. As a representative of the procrastinators, I will now stick my tongue out at you - ^,^ - Thank you for your time.
P.S. Very well done on getting such cool DDR pads! =)
P.P.S. Very sorry about that double-posting. My computer froze up and I assumed the first post wouldn't have been processed. *blush*
Oh, believe me, Magenta - excuse me, *magenta* - is not one of those annoying people. :D
I only not procrastinate when it suits me.
i.e. when it's linked to something less fun than playing DDR?
Yeah, like, say, home renovations, or job hunting. :D
And now, redneck poetry!
Tickle, tickle, little 'pine
How you doin'? Hope yer fine!
Down in that thar state so flat
Dancin' on yer 'lectric mat
Tickle, tickle, little 'pine
Do yuh soak yer cats in brine?