Talked to my group and they're really interested in playtesting. Also I've got an idea for a new kind of challenge to put into crawls. The defensive challenge, where you see how long you can last, and then that time is removed from your time in a time base crawl. The team must decide how much resources and damage they want to trade for time.
You could call it the Test of Thermopylae or the Spirit Challenge of the 300. The PC's bid how many waves they can withstand, starting at 3 and increasing in groups of 3, then 2, then 1 at a time with the encounters becoming more difficult at each tier. For each set of waves they withstand they receive prizes on an escalating scale and if they survive the entire challenge they receive x minutes (x equal to the # of the final wave they finished) off of their final time, if a times even, or 1 point per wave they completed (if it's a scored event). The Test may only be invoked (the players must ask for it) either at the start of the XCrawl (before they leave the green room) and then continue the crawl directly after the Test, or when they find a break room, they can call for the Test instead of using the break room, and then continue the crawl directly after the Test. The Test can only be called for once per crawl per team, and if the team falls during the test they are eliminated from the crawl, because if you die, you die!
So for example if Big Al and the Hitmen called for the trial as they were about to leave the green room, and bid 10 waves, they would fight 3 encounters back to back followed by a 30 second (5 rounds) break, then 3 more encounters, a 30 second break, 2 more encounters, a 30 second break, 1 encounter, a 30 second break, and then the final encounter. The first set of encounters would be at the CR of the group and each set of encounters would increase by 1 CR after the first. So if Big Al and the Hitmen were a 4th level team, the first 3 encounters would be CR 4, the second 3 would be CR 5, the next to would be CR 6, followed by a CR 7, and finally a CR8, a real challenge indeed! Prizes would be accrued at the end of each set (3,3,2,1,1, etc) and all prizes can be claimed when the group finishes the dungeon level they are on. Pass the Test, but fail the level and you receive nothing. The gods of fortune are fickle at the best of times.