Several years ago on this B forum, a guy in New England addressed the same problem. He designed, built and sold an add on kit that provided the necessary lift for the spare. You might search the forum archives and find some information, but I think it was probably ten years or so ago.
Also, I thought later model RTs with the continental kit were equipped from the factory with a similar device, but my memory may be wrong.
I am still comfortable raising ours manually and I wouldn't give up the storage space for anything. Our RT has twin beds and the available storage space is really large. No spare in the back for me.
WHOOPS! After posting the above I got curious and found an old blog post that talks about the lift and the guy that made and sold them. Past tense. Apparently he went out of business a few years ago and McAfee Security alerted me to that the old business website was now very unsecure.
Maybe someone has an idea where you might get something?