Kay,
only moderately nuts. With all the right parts, it's got to be technically feasible. The questions are: how long are you willing to have the car cut to pieces, and how much are you able and willing to pay? The dash has to be swapped over, and probably the bulkhead (or perhaps pieces of it) and maybe parts of the front floors(?). So gut the dash, probably remove the windscreen and surrounds, remove everything close to the bulkhead including the engine/trans, then start cutting and welding. You'll need the RHD exhaust manifolds and head pipes, they exit forward instead of back, or something like that. You may have to find, or make, or have made, a new under-dash wiring loom, too. I'd make a wild guess of 2-6 months in the shop and in the neighborhood of US$10,000 - $15,000. Add 25-50% for contingency and extras.
Since it isn't my money, I say go for it, and pleast take a ton of digital photos to document the process, and post them here, of course!
George Davis
'69 280 SL Euro manual