Pfft. Have you see the war chest that FOSS has built up? If they let even fired a third of that at Microsoft, old Redmond would be a cooked goose.
There are several. Bundyo posted a link to one of them above. On a side note however, OEM's aren't going to abandon FAT for an open source OS. Not that they don't want to. They'd love to get away from paying royalties to Microsoft. However, they know that 1) everyone else is using FAT, so they don't want to risk loss of compatibility. 2) It'll be a cold day in hell before Microsoft will natively support any file system but their own (unless supporting that file system somehow benefits them). Which means that OEM's will likely have to ship special file system driver disks with their products and convince people to install them. 3) Most end users are lazy, so option 2 is not an option, since most would rather go with a competitor who uses FAT than have to install anything to their PC that makes them compatible if they're not already.

So the only real solution here is to either force native support for Ext3 and other file systems in Windows (Ref #2), or make sure that Windows is no longer the dominant OS. Option two will come in time, but it's going to get quite messy before we get there.