largest map size people will play

[mercurycs]

just wondering , if I were to create a map for everyone, what size people would like it. I mean, how many provinces are too many? i can do upwards of 500 or so if people will play it, i have my old D&D world on my computer that i made with Fractal Mapper some time ago. I was going to plunk it into photo shop and do some editing and want to make a map for everyone to play. It is a whole world, not just a continent so i can turn it into as many provinces as people think is necessary. It is big enough for 1000 or more, but that may just be too big. I've got plenty of time...let me know how big is too big.
It is kinda grainy at such a high resolution, but the map is now about 5500x2600 pixels right now. I'm trying to smooth it out and may even give it a watercolor feel. its only about 4 megs in size too.