wait wait, i didnt know 32gb SD cards would work in the Wii.. damn! and I probably could get a 16gb Flash Drive.. will have to look into it more..
The Wii itself supports the larger SDHC cards just fine. I'm using a 32GB card right now. IIRC, the need to have a non SDHC card (thus a smaller card) was because the main exploits (twilight hack/smash stack/etc) were done through games which do not themselves support SDHC cards.
I know I had to run the initial hack itself using a 2GB non-SDHC card anyways, I tried it on an SDHC card and Brawl couldn't see the card.