Speed 900's ain't available anymore.

If you want commercial available drives to go, you have the Ranglebox Saturns in the UK.
http://ranglebox.com/product/saturn-...etary-gearbox/

For others, you are looking to the US.
http://www.robotmarketplace.com/prod...rs_geared.html

But don't worry, normal batterydrill motors/gearboxes with some work do the job fine in feathers.