Is farming Zoltun Kulle more lucrative than the Butcher in Inferno?

Yes, mainly because Zoltun Kulle is an act 2 boss. Act 2 drops can yield tier 17 items, where act 1 can only yield tier 16 items. To get the best drops possible you have to farm act 3.

While the drops probabilities should be somewhat equal between the two, the second one can drop better items

Didn't want to answer my own question but it was to long for a comment and it seems other people are interested as well...

So I, a tank monk, have been running Zoltun Kulle with my mage buddy today and the results are very good so far. We've only done 7 runs so far but the drops we are getting are vastly superior to the act 1 Butcher drops.

I knew they would be better, but we weren't sure if you wouldn't start seeing quality gear until acts 3 and 4. So far we've found 1 set item, which was exciting for us since we never found any in act 1 and all the legendarys we found in act 1 were level 55 and 56. We are also finding much higher quality yellows that we've been selling from 100k-750k so far, much better compared to the 20k-100k from butcher sales.

As far as just gold being found and vendor sales, I earn a little, but very slowly, and my buddy the mage loses money due to repairs and potions. The vast upgrade in drop quality has more than made up for this though.

I'd still like to hear other peoples opinions and results.

I have found farming Kulle to be atleast as effective as farming Butcher, and a lot more fun due to the challenge and exitement for good loot. I'm a wizard with 36k dmg, 24k health and 300 resistances, and the gold drops more than make up for my repair costs while playing with a tank and another ranged.