Both take mini-SD
1. As far as what brand names these things are sold under, who knows! There's so much overlap and copying going on I couldn't even guess.
2. Sure looks like it. Even use the same picture in the ad.
3. M2803-3.5mm M3201 -2.5mm
4. Never seen that one from a wholesaler :-(
5. I'm actually running out of stuff right now. All the M2803's are spoken for. These things are selling like hotcakes!
-Best bet is the PA20 from MP4Nation. $150 for the 4GB is a pretty good deal.
Also, check
this one out...