COD Deadly, as much as I want your business, you'll be safer waiting. There's a chance that NOBODY will have a mod for CODMW2. Maybe there will be no single-fire weapons, and rapidfire will be essentially useless. Maybe the game developers will release some super-awesome detection patch that stops rapidfire controllers from ever working.
Or maybe the game developers are idiots and rapidfire will still work just like in COD4 and COD5.
Regardless of buying from us or the competition, I would definitely wait to buy one. If you absolutely can't wait, then you should really invest in an upgradable controller. Right now I believe Viking360 is still the only upgradable controller.