the rims of a a mtb might not be that much stonger. A lot of the hits a mtb can take is due to the suspension and the wide low pressure tires.

also beware of racey XC hardtails. the geometry on many of those is more streched out than you think.

also don't worry about the cranks and stuff. if you are new, heck even if you have been around for a while, i doubt anyone spins out the top gear of a mtb. 44/11 isn't very far off of my 50/12. unless you are planning on going for long rides averageing over 20+ mph the low end of the mtb cranks will help you more than the high end of the road will.

a hardtail works great as long as you don't plan on going very fast. they also tend to be more cost effective imho