from what I have observed, the problem with mith golems in mith's anvil is not only spawn #s, but density. I have recently finished up two and half complete suits of gear (armor/jewelry) requiring 50+ mith frags. I find that there are 2-3 spawn locations where you will commonly find 4-5 golems packed together, then no golems everywhere else. I managed to get my frags no problem (with a large amount of time though), but you have to learn the spawn areas. I figured out that when I killed 4 in one place, there would be another 4 spawning in a different location shortly.