I know that backing up the wallet.dat file is enough, but I don't know if there are other accout-specific files in the datadir?

__db.001   __db.004   addr.dat   database   wallet.dat
__db.002   __db.005   blk0001.dat   db.log
__db.003   __db.006   blkindex.dat   debug.log


This is related to my OS X post here: http://forum.bitcoin.org/index.php?topic=16258.0

If the Wallet is the only account-specific file, then I'll use a symlink solution that should be much lighter.