yeah, thinking about it I've been riding deraillier gears for 5 years and never had any problems other than a bit of maladjustment of the indexing (soon fixed with a general service at my LBS). Also there's lots of room for customizing so if i am struggling I can always get some lower gears.
A steel MTB would be great but I can't find one - I live in Okinawa and all the new bikes are aluminium (which cracks, grrrr) and all the old ones are too small for me (only 6' but that's the tall end of the scale for okinawa)
I am now thinking about x'ing a japanese mama-chari (similar to a dutch shopping bike) using the derailier gears from my sirrus - could have real novelty value (and be a cheap way to get what i want) tho' not exactly street cred.