Hi Steven, welcome to the forum.
To be honest, I'm a bit reluctant to offer my take on the best hardware, especially for LR4. One of the oddities of the LR4 performance issues which are still affecting some users is the fact that in a lot of these cases the hardware in use is actually quite highly spec'd....certainly much higher than my first gen i7 system. The other problem is that performance expectations are generally quite subjective, i.e. what may be perfectly acceptable to me may be totally unacceptable to you.
So with those caveats in mind:
CPU...I use a 4 core system with HT, and have found that LR3/4 will happily drive all 8 processors. I expect that on a 6 core system with HT that LR again will happily use all 12 processors (I think Victoria can confirm that when she gets back). So either of your 2 options should be viable, and given that they are way more powerful than my (now modest) system, either should perform well.
However, with such a powerful CPU the biggest problem by far will be feeding data quickly enough to make best use of all that power. Even with my first gen i7 I have never been able to max all 8 cores even when doing high-activity tasks like multiple exports....LR4 gets me closer than LR3, but it never gets red-lined. The problem in my case is that my 4 internal drives are all standard 7200 drives on a 3gb/s bus, so if I was bothered by this I would be looking at adding either SSD or 10k drives into the mix. That may be something you'd need to pay attention to if going for a very powerful CPU.
RAM....I have 12gb and that is probably more than enough. 64gb, IMO, would be a waste of money unless you have something else that would use that amount. If I was building a new system (maybe next year), I'd probably be looking at 24gb maximum. So the fact that the 3770 only supports 32gb just wouldn't be a factor in my decision-making.
Hope that helps.