Maybe this is not what you want if you are looking for crewmen at work (in acction, I mean) but if you want some nice figures to set your aircrafts, please try to find Hecker & Goros (from Germany) figures in 1/48 scale.
I remember Hecker & Goros has a set of US Bomber Crew plus several sets of US pilots and mechanics. About the bomber crewmen, I am not certainly sure of it now, but I think they have even one belly gunner... They are white metal figures, but do not panic, sculpts are great and detailing and casting is superb too. I have many sets of Hecker & Goros and no complain until now.
You can try to find them here, my favourite 1/48 scale on-line store for figures and accesories.
And I think SOL Productions (from korea) may have more bomber crewmen in 1/48 scale in resina, but much more Memphys Belle fashion, but I cannot confirmed it now, I may be wrong.