Ok, thanks guys, sonuds like they just don't make them. However, according to the spec, there are usually two 5V pins on a laptop, and on a desktop there are those and and two 12V pins. More than enough power for single 2.5" drive, and enough for a single 3.5", but probably not enough for two 3.5" drives, as you said. I'm not sure how much power they require.
If they made a RAID array with two 2.5" drives it would work I believe. Oh well ... looks like I'm going with an internal setup. Thanks very much for everyone's input.