Is it possible to swap SMG III into Manual?

Hello, I live in Europe, and here all E63 M6 are with a SMG III. I am considering the purchase of an M6, since I believe there are very few cars in the market that are somewhat sportscars / GTs, with the ability to seat four people and non-aspirated. However, I like manual transmissions.

I have heard that in the US the M6 could be bought with a MT.

Do you know if it is possible and feasible (in cost terms) to swap an SMG III for a MT? I imagine one would need to purchase the whole transmission, change the ECU, add the left pedal and change the whole interior for the stick (and I am sure other things, too).

Has anybody done that? Is it possible to estimate the overall cost?

Thanks.