Hmmm, I do more imaging then visual - off a 9.25" SCT I put a Feathertouch fine focuser (reduced mirror shift / flop considerably too) but put a meade motorfocuser -> Lumicon OAG with a DSLR and a Meade DSI II Pro guide camera (and run the meade focuser via a JMI -> USB converter into a PC). So I focus never having to touch the tube with an Bhatinov mask.
That's a bit of gear a fair way out from the focuser. I routinely do 20 - 30 minute subs and see no issue in flexure of the focusing rig. My scope is Carbon fibre - and it holds focus across significant thermal range. Basically I could probably adjust focus once a week and find things have barely changed unless the weather soars or plumets - it amazes me.
I am unsure how you judge the calibre of gear you need for the tasks you envisage. But the rig I have does keep half a kilo of gear about a foot from the rear of the OTA securely bound.
So thats a $300 unit plus a $100 USB converter to give you computer controlled focusing.
http://www.bintel.com.au/Accessories...oductview.aspx
plus
http://www.bintel.com.au/Astrophotog...oductview.aspx
If you wanted to go all out - ask Mike Sidino what he uses - or consider
http://www.optecinc.com/astronomy/catalog/tcf/tcf-s.htm the TCF temperature compensating focuser have a pretty big reputation.