OK, it could simply mean that they've not been able to secure anyone yet, but Hearn is saying it's due to negotiations with good names, so if we're to take his word for it, any guesses on who it might be?
Herbie Hide (officially a CW now but might fancy it -he hasn't got any better ideas)
Rogan (why not -he will fancy winning it again and also doesn't have any other obvious avenues)
Larry O (unlikely since the man himself has repeatedly said he's not interested in PF, but we all know he'd make an exciting addition)
Fury (no chance)
Dallas, Towers, Price (highly unlikely)
Barrett, McDermott, Krence (would be reasonable additions but not "big names")
A UK-based international HW (Perez, Sosnowski??)