[quote="drmini in aust"]Mini roofs were resistance welded in the factory with a special type of resistance welding machine that did overlapping spot welds.
The common way to change a roof at home is cut carefully through all the pillars and transplant one from another car.... known as a cut and shut.[/quote]
I'm with the doc here. Pre 74 cars are spot welded, so you can drill out the spot welds and remove the bad roof and bring in a newby. You can drill the laping flange (the bit where its welded on) in the same places as the old roof and the braze it on at the holes, just remember to clean off the brazing with deoxidine and then metho and then thinners to make sure you have removed all traces of the flux, otherwise you might get problems with the paint not sticking and then rusting again. But it will look 99% original. Other thing to remember, while the capilary action of the brazing does help with sealing, don't forget to seem seal it and don't accidently block up the gutter in the process, otherwise you'll need another roof!
Don't know if that applies to your mini though... Is it an SS? Did it have a spandex roof? Mine didn't have one when I bought it so I didn't have any rust to worry about. If its an SS I'd do what the doc is suggesting because the rooves weren't spot welded at that point. They were resistance welded.
PS, they glue alot of panels onto modern cars from the mid 1990's onward (there is the odd earlier one) pretty cool hey

? The thing is that they are designed to be glued together and they work well that what way. Minis are designed to be weld together so it might be a problem...
Just a thought. Thats all.