I will try to win a military lot with dummy loads that's coming up, I
really need one for my home lab and will sell the rest of them. I
could them pick up the amplifiers and the dummy loads in one trip. Is
a wattmeter separate from a dummy load? IOW, a wattmeter does not have
its own load, it plugs in between the signal source and dummy load, is
that right?

Yes, there are dummy loads with built-in wattmeters but probably not
appropriate for your project. As to RF wattmeters,
http://www.radiodan.com/Henry/misc/bird.htm

That Harris, as I just learned, has its own display that displays
watts. So, if I have a dummy load, I would not even need a power
meter, if I am to trust Harris's display. It would be nice, although
by no means required, to compare Harris's own idea of its output with
an expernal power meter. I have not seen a 500W power meter anywhere
yet though.

Again: http://www.radiodan.com/Henry/misc/bird.htm


Also, it would be nice to be able to monitor the supply
current.

A great idea, in fact, I own a kill-a-watt inline electric meter, it
meters watts, volts, hertz etc.

Sounds like a fun project! Good luck!