You also have Warwick Black Label strings, the 40240 LB (Low B) set: .065", .085", .105", .135"
http://www.warwick.de/modules/produk...ID=14510&cl=EN
Along with the Rotosounds mentioned above, these are the only ones I know factory assembled for this tuning.
I'm going along that path too, but still undecided about which set to choose. Why don't you personally like the Rotosounds (never tried them myself). How does your bass cope with the set-up?