I haven't tried cards that big.You could PM fat16lib and ask if he's tried it that size card.Check his recent posts too, he put up some test results very recently.
Here is fat16libhttp://code.google.com/p/fat16lib/
Remember FAT32 is limited to files no larger than 4 GB so you will need eight or more files to fill a 32 GB card.Recent versions of SdFat also supports SDXC cards when formatted FAT32 with the SdFat/examples/SdFormatter sketch. FAT32 is not the standard format for SDXC cards but PCs, Macs, and Linux accept FAT32 formatted cards.I have tested with 64 and 128 GB SDXC cards.
I have a general understanding of FAT32, but not the Arduino implementation.