As in all items, the further along in the game you get, the better chance you have of good drops. Hilts and pommels, or any weapon upgrade for that matter do not drop by themselves...you have salvage them off of a weapon yourself. As for the hilts/pommels you mentioned, those are probably the rarest in the game for swords anyways. A +30 hp pommel is super rare and is selling for more than 100k gold these days.
please just go and try a few areas ... posting farming spots is not the best idea. and you can get some rare items from lower level characters ... i have farmed the desert till the cows come home for useless stuff ... i agree re: the whole southern shiverpeaks is a good spot, due to its massive amounts of mobs all over the place ... pick your flavor. However I have received many other items from low level creatures 14ish including but not limited to staff wrapping enchanments last 18% longer, bow grip of marksmanship (20% chance using skills), and zealous bowstring 4/1
I mean these are by no means a +30 fortitude butyou get my drift ....