Hi Mark,
I have heard about the Televue Dioptrx Corrector from a couple of guys that tested it out at NEAF recently. Unfortunately I am using Pentax XW's with my glasses on at present and the TV device cannot be fitted to these eyepieces. There is another device produced by Mark Gibson's company, Clearvue Optics, which fits into the focuser, called the Astigma-Cor which has been available for a couple of years but I have not received much feedback on it, apparently it also only works with "simple" eyepiece designs, but at least of any manufacture.
http://www.clearvueoptics.com/prod01.htm
At the moment I am very happy with the Pentax Eyepieces but I will definately try out these devices when they become a lot more widespread amongst the Astronomical Community.
CS-John B