Paul,
there are a couple of integrated focuser /rotators on the market which may be worth considering..
A 3" with a 74mm total height:
http://www.reginato.it/accessory.html
Planewave also do a beast of a 90mm focuser / rotator that can lift almost the same weight as Mike.
http://planewave.com/products-page/g.../#.U3asf1AZ7qA