I first read a variation on this scenario back around 1982 in an Omni magazine article. It'd be quite difficult to launch something into a retrograde geosynch orbit from the Earth's surface. However, the article mentioned an interesting idea - loop the payload around the moon to return it to a retrograde geosynch orbit. You'd still need to so some fancy maneuvering to circularize into a retrograde orbit, but it could theoritically be done.

Many geosynch satellites do have a few degrees of inclination. Left to their own devices, a satellite in geosynch will have its inclination increase by roughly 1 degree per year on orbit. The groundtrack for a satellite in an inclined geosynch orbit looks like a figure 8, with the size of the lobes being equal to the inclination. If you look at the inclination parameter (2nd parameter of the 2nd line) of NORAD two-line element sets (TLEs) for geosynch satellites, you'll see inclinations of over 5 degrees being pretty common and some of them are over 10 degrees inclination. That inclination would make it harder to sweep through the geosynch belt and talk out all of the satellites. If they were all at or near zero degrees inclination, it'd be a lot easier. Fortunately, that isn't the case.