It sounds feasible to me as long as you have the resources. If by pavers you mean brick style pavers, you'd be talking about a bunch of them plus a bunch of sand. A 30 foot(360") circle would have a circumference of around 1,130 inches. That would be around 141 4"x8" pavers just for the outer circle.

Each successive ring of pavers would reduce the diameter by around 8", and the number of pavers needed by around 3, so the second ring would need around 138 and so on. You're probably talking about nearly 3,000 pavers. Regardless of what kind of materials you use, it would be somewhere in the area of 640 square feet, the equivalent of about a 25'x25' patio.

If you want to use sand to bring the middle level with the pavers, you'd need some kind of edge around the inside of the inner circle to keep the sand from washing out from under your paver ring.

It would be kind of expensive. Around here the 4"x8" pavers are on sale at one place for 33 cents apiece, so at that rate it's about $1,000 just for them. I have no idea how much sand costs in the volume you'd need, but you would probably want it at the very least 2-3" deep. That's around 4-5 cubic yards of sand.

If you could afford it I'd probably have a pro do it, and I'm as gung-ho-I'll-give-it-the-old-college-try as anyone out there. I've done a small area using paving blocks and just sand but your idea, which would be something of a focal point, I'd want to be sure was done right with a gravel base, then sand. It would be even more expensive, but worth it in the long run.

I, too, wanted to do this...so I searched online for info, and I found a great website with GREAT instructions on how to build one. I used this to build our own. I had to modify a little bit because we had a pile of landscape blocks given to us, and they weren't as large as these in the instructions. But it's GREAT!

Here is a link that might be useful: Fire Pit Instructions