OK, DIY boys and girls, Nelson Pass has released the "F5 Turbo" project to the DIY community through his FirstWatt commercial site. He describes theoretical scaling of the modest 25w class A F5 to as much as 1KW in a balanced V3 mode

See link to F5 Turbo here:
http://www.firstwatt.com/articles.htmlNote the classy dedication of the project to Ed Dell who has himself brought so much to the DIY community. His address is listed there to send him a birthday card and I hope many do so.
I've built at least one of every Fx amp he has given to DIY'ers. I'm about out of big heat sinks, but this is certainly tempting for a long term project. 100w is very achievable with sufficient sinking, while retaining the simplicity of the original circuit.
Anyone here thinking of jumping in?