According to a post on DS:
"The former HMs who have so far signed up for BB11 (if my info is correct - which is open to conjecture) are:
Nick Bateman, Craig Phillips, Brian Dowling, Helen Adams, Jon Tickle, Victor Ebuwa, Craig Coates and Aisleyne Horgan-Wallace. Pencilled in & very likely to also appear: Pete Bennett, Anferny Hutton, Shahbaz Chauhdry, Brian Belo, the twinnies, Mikey Hughes and Charley Uchea.
Some will only be making short guest appearances, others will be entering the house to spend significant time with the new crop of HMs. None of the former HMs will be eligible to win...but the most import rule of BB is that Big Brother can change the rules at any time."
Link
Most probably bollocks though.