We have a large festi family too. Telluride Alpine Lodging is where to start! They are the most helpful awesome people. We called with our budget and they helped us accommodate our family of 9+ for 3 years now! They even have condos with 5-6 bedrooms, if you can afford the luxury. We rent a 2 bedroom. Give the older people in the group the beds and everyone under 40 grabs floor space with a mattress pad set up or couch. Sure, its a little tight but you're not there to be in the condo
We've done others but I feel Telluride Alpine Lodging makes it easy and hassle free, I know everything will be ready and set when we get there for our 8 day vacation
I wouldn't wait though, get started now! You won't have much luck finding a condo in Telluride (you'll have to stay in mountain village) after the end of the year, probably sooner.
There of course are other options. I've checked out Craig's list vacation rentals and other sites. There are a couple different lodging companies in Telluride too. Also, Check out lodging and accommodation sharing here on the planet bluegrass forum.
If you have any questions feel free to pm me