Dave Thatcher is the designer of the Thatcher CX4. On the CX4 Yahoo Group, Dave posted the following on 3/15/2012:

Gentlemen:
The CX4 kits offered by Mr. Peter Beck will no longer be available.
Of course, the kits sold and under construction now will be completed.
The fiberglass parts sold by Erni Martin will continue to be sold, and the parts
I make will still be available.
Best regards,
Dave Thatcher