I don't think there are any Forth CPUs available on the market right now. There are several designs to produce one with FPGA or CPLD. I'd love links.
Chuck Moore is designing an array of 25 Forth cores on one die. But all the information about it has disapeared, because a potential manufacturer wanted it that way.
On the Forthfreak wiki is a page, listing several Forth CPUs: -- http://www.forthfreak.net/index.cgi?ForthCPUs
Samuel A. Falvo II is planning to make a Forth CPU (out of FPGA) as part of his Kestrel project.
The p24 is a nice little MISC designed for FPGAs: http://www.eforth.com.tw/academy/sutra/chapter9.htm
"b16 -- A Forth Processor in an FPGA" by Bernd Paysan 2003 (designed in Verilog) "The b16 Processor is a minimalistic stack processor, inspired by Chuck Moore's recent work." -- http://b16-cpu.de/
"An 8-bit Stack Processor" by Steven Sutankayo and Rob Chapman apparently designed in VHDL http://www.compusmart.ab.ca/rc/Papers/8bitprocessor/stackproc.html
Forth Chips http://www.ultratechnology.com/chips.htm seems to point to many CPU-in-FPGA projects
"The J1 Forth CPU" by James Bowman "A small, fast Forth CPU" http://www.excamera.com/sphinx/fpga-j1.html
Writable Instruction Set Computer http://c2.com/cgi/wiki?WritableInstructionSetComputer