i wouldn't think an f1 beddy collie would be the quickest for rabbits would it ?
i don't think you have really thought this through have you? you don't see many (if any) of these crosses around, i think there is a reason for that. I havn't seen or heard of any rabbit dogs that catch rabbits on patience alone, they would have to have a bit of speed in the x to be classed as a decend rabbit dog imo. You say they are patient dogs, how do you know, have you worked this x before?