Battletoads raid: I still think it would be pretty lulzy to have someone (or more than one) in a Battletoads costume. I dunno what exactly is planned for the raid but, assuming it's going to include streams of people going in and asking for Battletoads, it would be hilarious to follow that with someone in a Battletoads costume walking in, browsing, then buying something and then leaving, as if nothing were out of the ordinary.
As I said, it doesn't appear that ANYONE is making/selling Battletoads costumes, and I can't find any home-made ones either. Seems that back when the game came out, they released a pattern for a Battletoads Halloween Costume and that is available on eBay, except obviously the measurments are intended for a kid's costume.
BATTLETOADS Costumes Size 10 12 Child Pattern 6155 - eBay (item 200347878849 end time Jun-30-09 01:51:35 PDT)
Probably 100% do-able if you're clever enough to adjust for size and change the measurements. The base of that costume is similar to a set of overalls, so you could save some time by simply buying some green overalls.
Other than that, you could try modifying one of the Ninja Turtles costumes that's also available on eBay, although they are a tad pricey:
BRAND NEW TEENAGE MUTANT NINJA TURTLES COSTUME SIZE XL on eBay (end time 28-Jun-09 20:12:03 BST)
To mod the above costume (using the below Battletoad picture for reference), you'd need to leave the rear shell off (obviously), extend the front 'shell' down so it covers the crotch (could do with being a bit more yellow), create a belt, modify the existing kneepads (they are a part of the suit I expect), add some green gloves and creat the spikey gauntlets (long enough to cover up those brown elbow pads) sew on some darker colour patches to get the mottled skin colour, and of course come up with a head piece.