I can't say for certain, but it is likely that the right 2gb chip will work in the mini right now. I remember when the iBook was rated for just 640mb max and the 1gb chips came out people started to use those with high levels of success.
As the 2gb chips are so expensive right now, your best bet is to just wait it out until someone out there does some testing to see which 2gb modules work with the mini.