A while ago I released a playtest version of a game I was working on called 'Those Dark Places'. The system used a single D20 (I called it the ODDS system - One Die Determines Success) and it had full rules for characters, vehicles and starships. I never completed it and never had any feedback.
If you get the chance, check it out and let me know what you think - you can email me at jonathan (at) farsightgames (dot) com. I'm thinking of digging it out and maybe using the system for my magazine format game, considering the fact that I have had no concrete info regarding Open D6 and no answer from Eric Gibson to my email from two weeks ago. I've given up on that system, now.