This isn't really feasible due to the time it takes. Backdrops already take us a LONG time - the choice is really between either filling in that HA gap or spending time cutting it out and smoothing the edges and uploading it as both male and female for the avatar.

Doing both would not only be a problem for the extra time spent on the art but also the time spent in uploading multiple versions of both overlays and items, descriptions for everything, checking and accepting and releasing everything - it's just not something we're going to be doing, I'm afraid. At least not with any kind of detailed backdrop.