jrichrds, I guess I should be less dogmatic in my posts, both here and on 3DSS, but I am much more sure that the KTXPro's=RShack Pro35's than I am about the older Portapro's=RS Pro25's. I know for a fact that Koss makes many of Radio Shack's headphones--you can even find the Koss imprint on many of them. I also know for a fact that the KTXPro's have identical specs (beyond the sensitivity, which doesn't necessarily mean anything), identical listed parts (down to titanium drivers, 6' cord, etc.), and that they look absolutely identical (down to the same rectangular volume control, the same headband, etc.). Also, the comments on the KTXPro on Amazon.com sound like the Pro35's that I know and enjoy.
Radio Shack also sells some headphones that look virtually identical to the Koss SportaPro's, and at a similar markup over the SportaPro's price. Atrac, you should check out the SportaPro's, which can be found for <$20.