Well it appears I'm a very lucky in more ways than one......
Went out this morning and replaced all the fuses I pulled last night, I added about 3 quarts of oil, this got it back up in the operating range, I was thinking about pulling the injectors as some had suggested but after awhile I decided to see if it would turn over, I hit the starter and it fired up just like always..... no smoke, no unusual noises..... I went to town and picked up some more Rotella Syn. and came home and changed the oil and filter, degreased the front of the tractor where all the oil blew out and power washed it, there was a small amount of oil on both the inner and outer air filters so I'll replace them.
It appears the engine is OK, the only explanation to this is indeed it had to be running on it's own oil and once the oil got low enough that it quit running into the cylinders (or out the vent line)the tractor quit, there was still a couple quarts of oil scattered throughout the engine so I guess this protected it.
I'm guessing the crankcase vent line is run into the intake air and the oil came through the vent line into the intake (the reason I have oil on my air filters) and was sucked into the engine that way, I don't think it blew past the rings, it had to come through the crankcase vent into the air intake, I may look at rerouting this as well.
I don't think a fire extinguisher is the answer to a runaway engine, the only real solution to prevent this from happening is an emergency air kill which I will be adding as soon as I locate one.
This may never happen again (I hope not) but the next time it does I will have a switch or handle to shut the air off.
Thanks for everyones comments and suggestions, I'll post back and start another topic when I locate an air kill.
Steve