How about 2d8 leopards or 1d8 tigers?
CR 11 is probably ok, though the hp might be a touch low. I think the special abilities probably make up for that.
It does indeed include weretigers, Cleon. It doesn't include any ordinary ones.
Tigers are 2 Challenge Ratings higher than Leopards, which suggests we need roughly four times as many leopards as tigers. Cut the tigers to 1d4 or 1d3+1?
Sorry, I think I got my Organization mixed up with my Summoning.
Actually, that gives me an idea. Tigers, at CR4, seem a little weak for a monster of its CR to summon. We've tried to make up for it by upping the numbers, but that doesn't work terribly well in 3rd edition.
Could we make it weretigers instead?
As you pointed out, tigers are a bit weak for their CR, so let's increase the leopards rather than decrease the tigers.
I'd rather not add weretigers to summoning, as it undermines their weretiger curse ability. I'd be OK with adding a dire tiger or two, though.
How about 2d4+4 leopards?