I think it depends on whether you're going to mainly store data on the drive which isn't being rewritten all the time... if you run cacko for example, you should be fairly safe unless you put swap on the CF.
if you really MUST put swap on the CF, partition it up such that you create the swap part'n right at the end of the CF card, so that if you do wear it out (you'd only create say 256MB swap anyway, any more is pointless) and get bad blocks, simply repartition and stop using that area of the card!
in fact, even if you did use OZ, provided that you ensured that the CF was formated jffs(2) which spreads wear, mounted it noatime/async and didn't have loads of file rewriting, you'd probably get away with it?
I've thought about this a lot, but would still prefer to try and get a hitachi 20GB microdrive which exist but aren't generally on sale.