I'm not really looking for a solution, just supplying some information in case anyone is contemplating a >16GB card.
Using Ubuntu 11.04 ARM or x86_64, I cannot create an ext4 partition that will mount. Doing fsck.ext4 appears to fix the filesystem, but rerunning fsck.ext4 a second time gives the same errors.
Only BTRFS works.
A BTRFS partition can be created without a problem. I then use rsync to copy across all the data from the 16GB (ext4) partition and it mounts without errors. After the rsync I create the excluded directories proc, sys, tmp, media.
I get a kernel oops (2.6.39-x1) on boot up of the 32GB card.
I'm still trying to figure why I'm getting the oops that I don't have on the original 16GB card.