02 4.4 Head Gasket?

[gnavejr]

I will rescue my X5 from a dealer this week. They want $20k for a remanufacted engine because they suspect cylinder/ring damage, because a compression check indicated 185psi on 6 cylinders and on the two suspect cylinders side-by-side indicated 140psi.
The truck has 151k miles on it, and stranded my wife out-of-town last week with white smoke and a "SES" light on the dash. No abnormal temperature indications. (Yeah I know about the inaccuracy of the indicating system). I called and had it towed to the nearest dealer. After several phone conversations with the Service Manager; I've surmised that I'd better get it home ASAP and check it myself.
I highly suspect a blown head gasket. I can only hope that this is the extent of the damage. If after a thorough visual inspection this holds true; I'll resurface and pressure test the head and check the block for straightness.
Has anyone else experienced this and if so, are there any obstacles to look for? Any tricks or secrets? Any help is appreciated.