You could also consider a magnetic stirring setup for agitation. I've never seen it mentioned before but I've always considered trying it out, I don't see why it wouldn't work (those bars may be small but you can get them going pretty fast).
here's the equipment you'd be looking at:
TROEMNER VWR 200 Mini-Stirrer 58940-158 4"x5" magnetic - eBay (item 320298483867 end time Sep-17-08 10:15:00 PDT)
Fisherbrand Magnetic Stir bar (76 x 13mm) 3 x 1/2" new - eBay (item 380062896661 end time Sep-16-08 20:40:49 PDT)
The electronic stirrer units are traditionally placed on the bottom of the container, but it would probably be a better option to tip the unit on it's side and have the stir bar on the edge of the tank.
This would probably be a good solution for agitating dyes as well.