what is the best way to remove heads that have been on the engine for probably 10 years and also buried in dirt for about 5 of those ten years?
I have tried soaking with wd40 and smacking with a dead blow hammer.....I tried wedging a screw driver between the head and cylinder but the cylinder just crumbles....

dynamite.

where can this tool be had?

I would just keep applying penetrant and using the mallet. If you dont mind replacing them, you can put a 2x4 against the exhaust studs and hit the 2x4, the risk being that you bend or break the studs.

I may do that its easy enough to replace the studs

I had a block that was stuck, and I did what Brian just described. I was able to get 3 of the 4 cylinders off. For the 4th, i used an angle grinder and I cut it off.

apply some heat with a torch, around the head and block smack with over size sledge

I've had MUCH better results with PB Penetrating Catalyst over WD40.....my two cents. Good luck

I am partial to heat myself.....Then cool it down with penetrating oil