I like the idea, but I think it is going to become very difficult to manage. Something that may help is for some frags to be sold to make the money needed for permanant equipment. That reduced the need to track who owns what and what if they leave, etc. From the selling forum (or through trades locally), you could pick up most of the equipment for relatrively low dough. IMO/E, you shouldn't need a skimmer. Surface skimming is essential, but if there is good surface agitation, zoas don;t need one. I ran Jenn's 20long with a CPR BakPak for a few years. The water had a stench that crept into your pores for hours and no soap could remove it. I put a surface skimmer (hooked up to a Magnum 250 HOB) and removed the skimmer and it has never looked better. Same with the 5.5 at work. The surface skimmer is the best $10 I've spent on a tank. If it has an overflow, that covers that, though.
Something to add is a top off. That is the biggest pain in runnign multiple tanks. A rubbermaid tub, small ph and a topoff switch, and you're good to go.
The most attention would be required around treating the corals prophilactically before entering into the system... One big potential issue is that one nudi or spider in the frag system and many many hours will be needed to rid the pests. They could decimate the entire tank in short order... Kinda scares me a little, but I'm paranoid of pest these days (though I've succesfully steered clear of the zoa pests, just have had everything else)...
I have, however, gone in with people on another website on Ebay auctions to get some of the cooler zoas that go for high dollar. The person who heads up the auction then holds the zoas in their tank until they are fraggable. Then the person frags them for those who put in and sends them out. There is some risk involved, but usually on the low end, monetarily. That doesn't put all eggs in one basket. Similar concept that is a bit easier to track.
Something like this may be easier to manage as more of a trading club where we could discuss locally who has what and wants what. I have graduated from the cheaper zoas into a wallet slimming spiral (Jenn says downward) to the more expensive ones (the $20-50 per polyp zoas). Without trades, there is no way I'd be getting these corals, though. That's where the Ebay auctions can come in handy. Though you have to watch for the chopshoppers and the tricks they play. We have been chronicallying several active Ebay sellers and it seems that there are several pahntom bidders that bid to raise the price, then pull the bid after someone bids higher. They also have sent messages to people saying that they know that someone else has bid X amount and that they are dropping out, only to try to goad people into bidding higher. Another thing they'll do is buy from one person and get the winning bid way up there (working in conjunction with the seller). Then the 'buyer' (who is in bed with the original seller) turns around and sells them a few days later because it is still fresh in everyone's mind how high they went for two days prior. This also drives the price per polyp up on certian morphs. These people have no scruples. Karma will have her way with them.
Anyway, off the soap box on that subject. Hopefully, you'll find some of my suggestions helpful and will likely throw others out...
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In this one each individual was responsible for growing theirs out. In success or failure growing it out, they would still benefit.
