As for the drivetrain - veloce is badly built, pure and simple. Pretty sure that tiagra 9v stuff works on MTB gear, or just use tiagra running gear with any long-cage shimano rear derailluer (105 and up is just as durable as slx stuff) with an MTB triple.

The BB and rings on deore cranks are made of some non-metallic cheese-like substance. get an xt/slx BB, or just an slx crankset.

spend a bit more on a719 rims. They're a lot stronger.