boot leopard from ssd!

hey guys, so i was wondering if it would be practical (or possible) to boot os x (10.4 or 10.5) from a ssd placed in the express card slot. that would be really cool because you could use your hdd for all of the media and stuff. it would also probably save battery on the startups. also, boot camp with xp on ssd?
this is actually quite intriguing because it it getting rather inexpensive.

here it is from crucial:
http://www.crucial.com/store/listparts.aspx?model=MacBook Pro 2.2GHz Intel Core 2 Duo (15.4-inch)