I once had Genji (who was my dream villager at the time and who I'd previously been resetting my campsite for weeks/months to try to find) turn up while I was trying to get rid of Pippy (my most hated villager who moved in through a WiFi misshap). I think I probably cried. Or at least complained a lot. x__x
I've also had Rosie turn up while my town was full but Genji takes the cake.
In my old town, Pietro showed up in the campsite and I was heart-broken because I really wanted him, but I had ten villagers.
Other then that, no. Most of the villagers I get in my campsite are horrible.
Baabara showed up and I was absolutely desperate to have her because I love sheep so much. There are obviously much cuter sheep, but I was trapped in a paroxysm of rage when I realized my town was full.