I watched him in Petersburg when he made the final, made hanescu look like a amature, solid returner, good movement, doesnt possess much power though in terms of groundstrokes but his serve can be quite effective,his main strength is his agility, making the final was a great confindence booster for him even though muzza mullered him in the final.
To answer the thread question, I think only Hanescu
have a half-decent shot at R4 out of that list, mainly because the two major threats in their mini-section are doubts for even starting. Regardless, as we've seen this week, Hanescu could potentially struggle against Monaco again, while it wouldn't surprise me in the slightest if Ljubicic knocks Kunitsyn out.
I see Bolelli
as the other serious contenders from your list, although I have reasons for doubting each of them. For Bolelli, it is no secret that he struggles with the big servers, and he has plenty of them in his mini-section. For Darcis...well, his form is horrible (and he is generally overrated imo), and I think one of Blake, Gulbis and Andreev will bounce him...although, in his favour, neither of those three guys are exactly reliable.
For Stakhovsky, I think Verdasco is likely to be too big an obstacle, but I guess I wouldn't be too surprised if he caused the upset there, and Stepanek isn't invincible.
As for the others...I don't see Golubev
going further than R3 (Monfils), and even an obese Almagro might be too much for him; I don't see Bellucci
advancing through Nalbandian (R2 and R3 respectively); Tomic
is likely to struggle against Starace, but if he does survive, I think Muller/Lopez would be too physically strong for him (Lalo in particular); I don't see Muller
getting past Del Potro (R3), but I think even Lalo (R1) could prove to be too strong for him (in the clutch moments).