Though I believe the Avalon design is a significantly more expensive design. There are a number of shops providing an Avalon clone service... Just like there are a number that will provide Klondike clone services (once the design is final).
I am a little surprised there aren't any (?) Burnin clone shops. I thought his board was listed as open hardware, and I think his is mostly complete/tested?
I think burnin is going to release at some point. Then we will see burnin clones but the clones will be a little behind.
I think the cost difference for Avalon reference design isn't that much for larger hash rates.
The nice thing about Klondike and Burnin is it lets the smaller operation participate in bitcoin mining at reasonable cost.