the dark aeons drop armor with break hp limit and sometimes even ribbon quite often. i managed to get at least one armor with break hp limit on it for each of my characters simply from fighting the dark aeons...

alternatively, u could fight Shinryu, who drops 2 wings to discovery for an overkill (that means you have to overkill Shinryu 15 times to get break hp limit on one weapon)

i wouldn't recommend bribing malboro's, unless you are very rich... isnt it 580 000 gil for 4 wings to discovery or something??