I have a second ds now so I am going to attempt to move my sheep, deer/goats, wolves, together, maybe some gators and tigers I tend to have many of the same types.
I did try once though from scratch to do an all bird town and it did not go well, I think I just didn't pick what I loved most it crashed and burned got annoying and now finally am looking for my last three or four to finish it but if I hadn't tried to do a theme wasn't so into with one ds cart would likely be done already.
I actually want an all deer town, but I think I'll miss out on one personality type... I can't remember which one it was. But I don't really care anyway c:
I used to have all the hippo villagers in my town, but there's only 6 of them. It got boring keeping the same villagers in town for me so I let them all go.
Goldie, Daisy, Portia, Cookie and Walker are all on my dreamies list! So I have thought about making an all dog town... no decisions yet, as I like to let the villagers come as they please.