Interesting. I've never played StoneQuest, but the idea of going further than a BL server sounds neat.
I highly doubt 6 people will work out though.
It's going to be highly debatable whether or not the modelers' models will be proportionate in size with other modelers' models, and if you have more than two coders, not all of the code may be compatible, often requiring a big jumbling of each contribution into one build, and people are going to be humping each other to get their input and ideas out. You also have no guarantee that these people have the skill to develop a project like this. Never done a team project for those reasons, but that's my guess.
It'll more likely than not be a disorganized mess, and never leave design or pre-alpha/alpha phase.
Good luck though.