The WA7 is desktop art, not a serious amp. The now discontinued ECP L2 is the only fairly comparable production amp to the mainline. Although employing some different tricks, both are highly regulated, constant current loaded, parafeed amps, running 6c45pi's, and designed by guys who really know their stuff.
I also agree with misterrogers that eddie current amps have a great house sound. If I didn't own a mainline and was looking to buy a [prebuilt] tube amp, I would look no further than Eddie Current (or ECP, whenever Doug puts out his next tube amp. As an aside, his upcoming Torpedo 3 hybrid kit sounds like it is going to be amazing).