Tone, there are almost no models of convertibles that come off of the assembly line as convertibles. Just about all of them are chopped by ASC in Michigan. I have seen the Mustang conversion building with my own eyes; taking a back road out of detroit once in the late 80's I saw a large building, with several hundred Mustang hard tops one side, and several hundred convertibles on the other.

The reason they look so good is they are done to high standards with manufacturer engineering and trim pieces supplied. They are done by hand, and the roofs are indeed cut off of a coupe.

ASC has done all the Mustangs of late and all the Toyota Celica convertibles ever made. i believe they do the Sebring and Solara as well. They leave their tag on the car; search around, typically on the driver's door jamb you will find it. Older logos says "asc" in lowercase letters with a red dot, spelling out "American Sunroof Company" in smaller letters. The new logo has changed along with their company name; here is their website:

http://www.ascglobal.com

They keep a low profile, but they offer hints about what they do in the "at a glance" tab. Note the convertible top stuff and the Toyota and Honda awards.

A few exceptions:
-Miata
-Cadillac Allante: a special case, designed from the ground up as a convertible, to a level never equaled before or since. It was a dismal failure in terms of profits.
-Honda S2000
-SLK

A special note on the new Toyota Camry Solara: This was one of the first vehicles ever designed to be chopped on the cheap. The trunk is reused, and some of the body stiffening is already in the floor. This reduced the cost of the new Solara by almost $3000 compared to the previous generation. Very cool.

Just about any car can indeed be chopped. The Vx is actually an excellent choice because it is a 2-door body on frame. However, no convertible will ever, ever ride as well as a hard top (except maybe the Allante).

Nate