Don't let them fool you...they're the toy poodles that sit on the laps of grouchy old women...
Only this time the old women have silly red tags and think they're an organized crime faction and the toy poodles have even less bite than you'd think...unfortunately they still have that irritating yipping and the bad breath...just do what I do...steer clear of them...
(or train their little two man bot parties)
Back to the original post...several clans/alliances are capable of doing 60+ RB's....there have been lvl 76+ on the server for long enough I'd be surprised if we don't see a couple noblesse rather soon.
Dominion I imagine can, I heard Invincible was doing them during the last event...but they had Zariche, Infernals can (even though they're Syn fanboys they seem to play their own toons so I don't hate them yet) Sleepers can, obviously Syn can...seems like GF could if they organized a bit...there are probably a few others....KarmaSutra possibly (not sure who they're allied with these days) Abyss didn't have the levels last I knew but they might now....a better question might be, "Of the clans that matter, who CAN'T do a 55-60 RB?"
funny thing you mention sleepers raiding high lvl raids.. cause my first thought was only botclans and maybe syndicate can do such raids.. and i was right. I have not yet seen one live Sleeper player out in the field. first i though i tell the leaders of sleeprs clan about some of their players botting.. but after i realise every single one of sleepers i've seen is a bot maybe you might be aware of it already :) GL