You can find the list of products eligible for the FIT here on...

You can find the list of products eligible for the FIT here on the website below. Bluegen is the only Fuel Cell product currently approved. The Baxi Ecogen and WhisperGen are both stirling engine based mCHP.

http://www.microgenerationcertification.org/mcs-consumer/product-search.php

However there are plenty of others such Ceres Power & AFC Energy who are rying to develop Fuel Cell products to compete in the space with CFU so it would be good if CFU got a commerical offering together for the Bleugen in the UK in the near future. http://www.cerespower.com/ProductOverview/ResidentialCHP/
http://www.afcenergy.com/news/

Actually, page 10 of this pdf has a pretty good list of residential mchp products so CFU being one of the first to market with the FIT approval should be trying to steal a march on their competitors in my opinion.
http://files.harc.edu/sites/GulfCoastCHP/CHP2011/Dehamma_ResCommCHP_CHP2011.pdf