Have been doing a little more research on this... it appears that the Korg nanoKONTROL2 is compatible with GarageBand if you install their control surface plug-in: http://www.korg.co.uk/support/downloads/nano2_dl.php
Anyone using this? I also found this old thread about problems with the Korg driver: https://discussions.apple.com/thread/2630372?start=0&tstart=0
Well I guess I need to answer my own question - do I get points for that?
For $60 I decided to take a chance on the Korg NanoKONTROL2 and I just received it from Amazon. Downloaded/installed the KORG MIDI driver, then the GarageBand plug-in. Everything seems to work as it should with no messing around.
It is somewhat limited, but gives full transport control and volume/pan for 8 tracks along with buttons for Solo, Mute and Record on each track.The pan knobs feel a little wobbly, but not too bad. All things considered, it looks and feels like a decent piece of hardware considering the low cost.
Maybe this will help someone else who is getting tired of using the mouse and keyboard shortcuts to control basic Garageband functions.