I got Destiny quest and it's really good i recommend it as i play the Lone wolf and FF paperbacks. You can also check out D&D castle ravenloft only uses one D20 though.
Arkham horror is fantastic once you get to grips with it(lots of dice rolling).
Runebound by Fantasy flight requires a lot of dice rolling on can be played solo with the variant rules.

I made a Dice/Card Game once called "Dice RPG". It was possible to play it single player, but was much more fun playing it against others.

Unfortunately, the game was only available in german, but with cute picutres. And the production costs were quite high, because of that the game was way too expensive to sell it properly.

I used to have books somewhat like the Choose Your Own Adventures but you had to make your character, buy equipment and roll dice to overcome obstacles and progress. I had a couple of Lone Wolf, and also one with Spider-Man that was fairly simplified in comparison, but still very fun. Not sure if that's what you're looking for.