I think two boats would be sweet, as far as timing... having that many people try get time off at one time could be a challenge.
I know that Neal, Laura, Jeff, Jess, Derek, Kayley, Steve, Travis and Matt would almost certainly want to go. The rest of the people that were on our boat are also possibilities. I could also see Tom and some other new faces coming this year.
As far as timing, August works best for me. And personally having been houseboating at the start, middle, and end of summer I have to say the middle of summer is the best (more expensive but worth the price in my opinion). I think the end of summer is also better than the start (warmer water, more beach, more people). But that's just me.