Dragon Warrior is done, but it uses the original/old code. I wanted to update it (there was one bug in how the last boss shows on screen, but the plays fine). Audio could use the new emulation code too. Anyway, it's low priority at the moment.
The emulation code is highly reusable, but each game does need a few couple of tweaks here and there. Not for the faint of heart. The problem is that you need to be familiar with both the NES and PCE on an advance level.
Did you have something particular in mind, or just general conversions?