I have not ran across any white smart 451’s yet. (except for a black/white cabrio, Busch #46175)
The Busch 450's had inter-changable body panels just like the real thing. The Busch 2007 catalog page 15 has shows extra panels for the 450.
Maybe you could buy the coupe that has the right tridion color and the white cabrio and do your own panel swap?
Here’s a link to the Busch web site.
http://www.busch-model.com/autoneu.htm
Note the only 3 ccoupe 451’s are in black, blue and yellow.
Keep in mind though this is from their 2007 catalog. If you go to the bottom of the web page you can download the entire 2007 catalog. They have a lot (over 80 or so) of the 450 models. These Busch models are HO 1/87th scale.
I have not found the 2008 catalog available for free download yet. Everyplace I find it they what $$.
Now from the research I’ve done so far the official “smartware” models come from 2 different manufactures. The HO 1/87th scale model come from Busch. The 1:18 scale models are made by Minichamps.
Hope this helps.
Ron #1175