The issue ended up being the brake hose had collapsed. The old hose is cut in this photo and you can kinda see how it is collapsed where this bracket wraps around the hose. I could easily stick a small screwdriver into the hose, but I couldn't get it to go into this spot very far...
At first I googled my issue and found several forms and other sites, many saying it could be the caliper, sliding pins, or even the master cylinder. A few people mentioned on some forums that it could be a collapsed or deteriorated hose, like I had.
To diagnose, jack the car up, pump the brakes, then try to rotate the wheel by hand. Mine did not rotate, but after a few minutes, the caliper backed off enough that I could rotate it.
Next, I pumped the brakes again, verified that I could not spin the wheel, and cracked the bleeder screw. A little brake fluid squirted out and the wheel could then be turned by hand.
Finally, a quick trip to the auto parts store, dropped $40 (yes... this rubber hose for the XL7 was $40!), and about an hour of my time, and the brakes are working just fine.
I'm planning on replacing the hoses on the other tires the next time I do some brake work.
Hope this helps someone!
