Dogfish's production has always been a little erratic. There was a period that even the Dogfish Pub was out of 60 minute! Kind of like McDonalds being out of french fries for god's sake! I actually prefer the 90 in bottle to on tap. Not the case with the 60 at all, which I much prefer on tap.
The 120 is actually slated for re-release in keg shortly according to the Dogfish website. They've dialed back on the ABV a little, apparently.
I know the pub often has 120 in bottle, and I'd be more than glad to pick some up for you. purplehaze1956 at yahoo dot com.