Re. using a flash card for you page file - bad idea. It will be slower than a fast SATA drive (by a large margin) because it effectively uses a USB bus and you will wear out your flash card rapidly.
Won't use USB if you use an IDE->CF adapter, but it's still going to be dog slow
- dunno about the amount of write/erase cycles - depends on media quality, wear-leveling algorithm and pagefile activity. I wouldn't do it myself, though.