Ok, basically Gen V is going around cloning old Pokemon.
Emonga = Another Cloned Pikachu
Buffalon = Cloned Tauros
Minezumi = Another Rattata Clone
Choroneko = Cloned Meowth/Skitty/Glameow
Munna = Cloned Drowzee
Mamepato = Another Cloned Pidgey
Koromori = Cloned Zubat
Mamanbou = Cloned Luvdisc
Kurumiru = Cloned Caterpie
Tabunne = Cloned Chansey
Monmen = Cloned Hoppip
Dangoro = Cloned Geodude
Yooterii = Cloned Growlithe/Poochyena/Houndour
Zorua = Cloned Togepi/Riolu (Do not quote. Personal Opinion)
Really they just seem to be randomly taking a few previous ones that were OK to underused (possibly) and made Gen V versions to them. It was confirmed that there are absolutely no Pre Gen V Pokemon and the Gen V Pokedex has 156. The total amount of Pokemon that was being made. So yes there is a very high chance no new Evos.
Once again the Gen V Pokedex was confirmed to have 156 places in it. It was on one of the updates that released info on the legends. It was confirmed that there were 156 new Pokemon being made for Pokemon Black and White. It seems pretty plain to me that there will be no Evolutions or Pre evolutions in this Gen.