JP,
My understanding is that the difficulty of a conversion depends on how accurately you want to reproduce the factory configuration. The closer to a factory Coupe/Roadster, the more difficult the process. You'll need an actual donor car for parts if you choose to install the well for the soft top frame and tonneau cover.
On the other hand, I've seen a far less complex conversion that doesn't look like the factory job but is very effective. Use the search feature as Jonnny B suggests. There are pix of it on this site.
The Coupe is an interesting example. Prices are generally lower than Roadsters, but they have the same pretty lines.
Douglas Kim
New York, NY
280 SL #016220