MORE O2 sensor crap!! Help!

[doubt at inwave.com (Nate Mellom)]

I tried to get my old sensor out today, first with a 22mm (7/8") open 
end.  No dice.  Got a real O2 sensor wrench from AutoZone, and succeeded 
in stripping the shoulders off the sensor.  Grabbed on with the biggest 
set of ViseGrips I have, and THEY slipped!  This was AFTER I dumped 
almost a whole can of PBlaster on it, AND ran the car to heat up the 
system, hoping it would help.  What the hell do I do now?  The damn 
thing won't budge.  Cat removal isn't an option, as the entire exhaust 
system is welded.
My next trick is ViseGrips and a torch, heat the connection and see if 
it'll break loose.
Any tips?
Nate
'81 (being good)
'88 (being a pain!)