I just learned that Steve Kenson wrote the magic chapter and d20 conversion rules for the new Deryni RPG. I haven't been able to buy it
I've always thought that True20 would be an ideal system for the Deryni setting, and hope that Steve will some day write conversion notes for the True20 system. Mechanically it would be quite simple. Just add a Deryni race background, some cultural backgrounds for the various nations, and tweak the power rules, and you're set.