@Mono: Cheers! It sounds like you've all been giving moving in together a lot of thought, and from what little I've read here you seem ready to me.
The best advice I can give (been living with my two primary partners for... almost a year now, whoa!) is to clear up all the business stuff (money, obviously, and chores and so on) to the greatest extent possible beforehand, and then talk regularly to update those decisions as needed. Of course you'll spend a lot of (likely more) time talking about those things once you're living together, but doing business together can be great too... I can't even say how much fun I have shopping for groceries with Z.
With regards to communes and the like, a concept I really found valuable in thinking about this is "cohousing"-- people have minimal apartments and share a common house that's fully decked out (most have a common room, a hardcore kitchen, laundry facilities, and a mail room... some have crazy things like guest quarters and playrooms and darkrooms). It's super cool, and I have ambitions of starting one with my extended poly family (which just got bigger officially this weekend-- my girlfriend just got a boyfriend! Squee!
The Cohousing Handbook
by Chris and Kelly Scotthanson (I have the revised edition) is an awesome resource on the topic; it's about actually starting a cohousing project, from getting people to getting land to getting moved in.