All that money and it's messed up.. that's gotta suck.
If the wet test stayed the same don't be too quick to point at the head gasket... Be absolutely sure the valves are correct on #4, a tight valve will leak compression too.
Oh it sucks, it sucks bad! I came very close to trading my truck straight across for a 98 chevy ext cab short bed with around 75,000 miles, great body and new transmission straight from GM... but I just have too much invested in this truck and I'm sure once I did trade it I would greatly regret it.
I will try readjusting the valves on #4 again, but this is just not looking promising. I really wish I had a different vehicle to drive so I could take a break from this truck, but we no longer have any spare vehicles so this one needs to stay in drivable condition.