I got 'em from
www.partsexpress.com
Try these:
http://www.partsexpress.com/pe/showd..._ID=1327&DID=7
and these:
http://www.partsexpress.com/pe/showd..._ID=1331&DID=7
If the above links don't work for you, go to
www.partsexpress.com and search for "lamp cover". You need the .2" covers for the instruments and A/C controls, and the .12" covers for the stereo. They're $1.70 for a bag of 10. I'd get like 3 bags of each, so you can double up if the dash isn't red enough, and have plenty of spares (I honestly don't remember how many lights are in the dash anymore). You might want to PM MattR about them and possible put a joint order together, since I know he's thinking about doing the same thing to the A/C and stero in his STi.
Once you guys get the covers, let me know and I'll be happy to help out with the conversion!