IMHO the A-26 is a bit unbalancing, simply because it becomes the only medium bomber used when it's available. I think the A-20 would be a far better choice (especially since it comes in 3 or 4 flavors--glass nose, gun nose, used by France, Britain, US) and the Mosquito was certainly a more historically significant plane, as was the Ju-88 or Pe-2.
Unless of course, we're simply looking for medium uberbombers, in which case the A-26 and, say, Ju-188 or Ju-288 would be good choices, as would the Mossie.
Didn't I read somewhere that the B-26 was going to be the next one?
--jedi