I'm planning to run a 2213 (B-Pack) motor on my XL Mustang as a test bed. The FliteTest BloodyBaron speed-build kit is listed as B-Pack capable. The XL Mustang is nearly identical in size to the original Bloody Baron. In theory, the B-Pack should be a good fit. If you try it before i get mine posted, definitely let us know how it goes!
The B-pack should be great. I ran the XL corsair off a 2204 and a 6x4.5 bullnose and it had unlimited vertical. A 2212 is cheap and would be even faster.