No, an Untethered is not available for iOS 4.3.5, a neither will there ever be.
All devices that are on iOS 4.3.5 are capable of upgrading to iOS 5.0/5.0.1,
iOS 5.0 will be the next untethered jailbreak, then iOS 5.0.1 / 5.X.X (depending on when apple reeases the nect update)
So to cut it short - an Untethered for iOS 4.3.5 will NEVER exist, so save yourself time by upgrading to iOS 5.0.1, when you an expect an untethered from 2-4 weeks