It's dead easy to do on a trad, I think Witter even made a kit for it back in the day. One morganeer got Kevin Vernon to fit one to his +8 to tow a custom trailer made from the back half of a Morgan.
On a CX platform I can imagine it would be possible, given enough expenditure, but it could never be a question of simply buying a towbar kit from a company like Witter. I wouldn't be surprised if you ended up having to completely re-engineer the rear chassis and then resubmit for SVA.
Legally and insurance wise it would of course be completely out of the question these days. If you want to tow with a Morgan you'd be much better off buying something from 1998 or earlier when it would be not only legal to fit one but also a great deal easier to do.
