Multiple Versions on Bukkit? I think I'll give it a try as long as I am motivated :)
(already decompiled the packet classes(net.minecraft.server. ....) and corrected about 500 errors(of 1500))

271021525s ago, by Antonio

...because of UUID "-"'s ...

loging in working until UUID check (for 1.7.x and 1.8.x)

dynamic versions in server list are working now :)
decompiled all files from net.minecraft.server. ...
and replaced PacketStatusListener files with manipulated (own)ones