I think it would be a brilliant idea.
You would accomplish the following:
- Destroy your resale
- Render your car invisible at car shows
- Confuse the DMV
- Get called a poser
- Regress the styling of the Crossfire by nearly a decade
- Spend absurd amounts of cash
- Create a completely confused character line throughout the side of the car
- Reduce the space behind the grille for intake mods
- Do an even worse job of marrying the two cars together than Daimler did in '03
Since it's your money, not mine, this is the best idea I've seen all day. I would love to see you actually finish this project.
There's your support. 
If that's still not sufficient, then perhaps you truly would be happier just buying a Mercedes if the badge means that much to you. Then, you could join THEIR forum and cuss them out for giving you an opinion AFTER YOU ASKED FOR ONE.
But seriously, you have my support. I'm sure the parts are cheap and abundant. Convert the coupe portion to the Vario Roof, while you're at it. Now THAT would be the cat's pajamas.