On the Yahoo site, there was a discussion of how to convert the hitch that was on a coach to a receiver style hitch.  For other's reference, I have posted pictures of the hitch that was installed on my coach, #1046, by RVS.  It is well made and securely attached.  I do not know when or by whom the original hitch was installed on my coach.

I am sure there are other methods, but it is critical that however it is done that there are secure attachments to the rear coach frame members.  Mine and the coach in question both are later coaches that do not have the hydraulic or shock absorber bumper mounting system.  An earlier coach with that bumper system would have to have a different mounting system than what is shown in the album named Receiver Hitch on $1046.

There is no formal weight rating for this hitch as it would take an engineering study to do such a rating.  The receiver tube is an off-the-shelf unit that is rated at 5,000 lbs.  I believe the attachments will support that towed weight in this case.