Here's one. I just purchased a Ryobi Oscillating Spindle Sander, Model OSS500 from Home Depot. Price was a whopping $99 I think this tool will replace my Dremel disc/belt sander as my primary bench sander. It has 6 different spindles from 1/2" diameter up to 3" dia. It rotates them at 2000 rpm and moves up and down 5/8". This appears to be perfect for shaping balsa, plywood, maple and other woods/metals that we use. This product is so new that even Ryobi's home page doesn't show it. It is on a plastic base, so don't drop it, but once it's in your workshop it should last a long time. It is very easy to change spindles and they are automatically 90 degrees to the work surface which is huge.
Bill
Bill