i believe there are some places that advertise in "The Star" the mercedes club magazine.
otherwise you might find some information int he dupont registry or the robb report on places that do conversions.
A lot of people have talked about doing this and have decided it wasn't cost effective or was too much of a hassle to do it.
Try searching for Grey Market or Importing cars and see what you come up with.
Search the whole forum, not just the individual sections.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.