one of the companies listed with Federation Models have photo etched sets for the Mobius kit and I remember that he had a couple sets of decals for Vipers.
Here's the original Monogram kit. I put in a cockpit and canopy, added the sensor screen in the nose, redid the engine plumbing with tubes, wires, and plastic, and added landing gear. To do the gear I used a copy of blueprints you could buy at the time. All went well with one side and then I discovered that the artist cheated. To save time he just copied the drawings into the other side. When you build them it just doesn't work out and you have to stop and figure out how it would look on the other side.
i213.photobucket.com/.../scan0358.jpg
I need to get hold of an old Viper kit to put on my launch rail kit I picked up from Federation Models.