Re: Campaign idea!
Brutal,
How are you going to handle the "Mysterious friends and enemies from the PC's past shows up sometimes" angle?
With any memory loss scenario, you run into the problem of the PCs grilling the NPC for info about themselves. Even a server who worked at a tavern the group used to visit would be able to tell them their names, how they usually interacted with each other, what they seemed to like or dislike (at least food wise), if they lived locally, when it was they came to the tavern (dates and/or times), etc.
The other option is to have frustrating 'near-misses' ... "Oh yes, there was a woman here who said she was looking for you. You just missed her though. She boarded one of the ships off of dock 9. I think she said something about Timbuktu."
Larkin