I know a bunch of folks who've quit MU*ing who would probably be all over a Requiem for Rome game if it got made. The main issue I've seen with WoD games (either traditional WoD or CoD) set in a different time period is they usually have a novelty effect for about a month or two, then people start to flake off of them in favor of Generic City By Night. However, I agree with you. I've had about four character concepts pop into my head with the mention of those time periods. It'd be great to play out; the issue would be trying to gather players for a somewhat niche setting.
What I figure is that the amount of research that goes into a character on a modern nights game would be greatly enhanced if it were set back in - say Trinidad during the Golden Age of Piracy. Depending on the level of realism you want, a potential player might have to research famous figures from the era, what might have brought you there, why you have any interest in being there at all, etc., which is generally a tall order from someone that just wants to get on the grid and buckle their swashes. That being said, I'll reiterate that I agree with you and would love to see something in a non-traditional era.