I used to use the drums myself, but I treated myself to the Wen portable oscillating variable speed spindle sander recently. Not the benchtop version, the small one. I think I paid $50 for it on Amazon. It obviously doesn't have the power of the benchtop version, but it really does have a very decent amount of power. The best part is that it comes with two clamps that you can use to mount it to the edge of a workbench or table with the spindle up. And it has a dust port that works pretty well. I absolutely love it.
It does have a few drawbacks:
It has a odd length spindle, so unless you buy Wen sleeves you'll have to trim them down to fit. I cut them down with my bandsaw, and all is good. Also the 1/2" is used directly on the metal spindle, so it has a tendency to slip rather easily. The 3/4" 1" and 1 1/2" all have rubber drums, so they slip much less.
It's well worth the $50 in my mind. Adequate power for most small jobs, and takes up only a little space. FYI: I've ground wood, stabilized wood, g10, micarta and aluminum with it. You have to go gently and let the grit do it's work, but I've had good results with all of the above.