Youz muzt be full of dat dere funguz' beer. Any git' wif' haf' a ead' knowz dat wif sum teef we'z can be gettin' sum of dem barg' combi-boltaz, we'z gona be tearin' thru dose' humies and sum of dem Defskulls too if yez not too carful' Dere' notz gonna kno watz 'it em' Da Bad Moonz ar' comin' boyz!
I think death skulls have a higher % of boys that are burna boyz due to them carrying torchs that can be used for cutting up stuff for looting purposes. As far as just fire not so much closest them come is they love things that go boom and burna boyz.
Since Freebooters are not an option, the obvious choice is Bad Moons. Fat, ostentatious, rich Orks with a penchant for firepower. Other Ork Klans seem a bit one dimensional to me, and Blood Axes are just un-Orky! Another unmentioned (and unplayable) Klan are the Snake Bitez. This group is the runner up to Freebooters/Bad Moons. Gnarled, tough squig and grot masters with a special affinity for Weirdboyz--what's not to love? Oh, and Cyboars... they need to put those in the Rogue Trader.