You can use the Action IV transport from the game, 'cause the Wild Karrde is
an Action IV.
The fact that there are no external distinguishing marks (unlike, say, a certain immediately recognizable YT-1300) was one of Karrde's big design features. He's big into subtlety.
Strangely, I don't think anyone's ever made a version with the three (hidden) turbolasers, faster sublight drive, better manoeuvrability, and readjusted docking points.
It shouldn't take much work for a half-decent Opter; just find a good schema to put the turbolaser hardpoints, add a "hangar," and modify the shipstats.