I have a 1GB Kingston SD card running just fine as ext2 on my Collie.
Bought it from geeks.com a year ago. Don't know model name but etchings on the back give a product code "SD-MO1G" (blurry vision..could be an MQ but think it's an O). But it's normal speed.
It loads slowly as I have so many files on it, but it does work. I really prefer using 512MB cards as they load so much faster for me.
If you want speed, use CF cards, they're much faster even at normal speeds.
sdjf