Exactly the same problem here...
Trackpad fine in OSX, and Microsoft USB Trackball unit works perfectly in both... the only problematic functionality I've got that has disappointed me IMMENSELY with my MacBook Pro, which I've had a week.
I'm a Mac lover by background, and do two jobs - Graphic Design and IT support (freelance). For the design I need a Mac. For the IT support I need a Windows machine, and instead of spending £800 (UK) for a decent Windows laptop, I decided to treat myself to a MacBookPro and double up a Mac upgrade (1st in 5 years or so) with a PC laptop all in one machine.
Brilliant concept and brilliant machine, but this problem makes this utterly unworkable as a solution. I can't just afford to sit around and wait for my trackpad to become usable again for a few minutes before it has another episode...
It's almost like it starts to fail in some kind of redundancy cycle, I almost wondered if it was some kind of issue with WIFI periodic refreshes, because the comms seem to also slow down signalling transfer rate at the same time, while functions like browser scrolling using arrow keys, and typing input do not seem to lag out at all...
I've only had it a week, but of course Boot Camp isn't supported software, so there's no guarantees with it. I just wish they'd come out and fix it, but it looks like I need to take the laptop back to the store (chain store electrical giant) and say that it isn't fit for the purpose it was bought for (they were advertising dual boot functionality) and that I want (spit) a Windows only laptop.
Anyone else find a solution to this.