By the way, this is exactly how Fantasy Grounds 2 and MapTool work (two popular tools for dnd-over-the-net).
I've tried MapTool, and been deeply unimpressed.
I don't recall all the details at this point, but it seemed incredibly cumbersome to get to work, and was a bit clunky in the interface.
A quick glance at Fantasy Grounds 2's website indicates that it's Windows-only—which isn't necessarily a showstopper, since Wine works very well these days, and I do have VMs, but it's a definite minus.
What
is a showstopper is that it costs money. I'd be willing to at least consider shelling out some for a tool that would let me host for anyone, but so far as I can tell, you need to at least buy a $25 "lite" license to be able to even play as a regular player.
Rolling my own will take longer, and not give such a comprehensive featureset as something like FG2, but it will be free for everyone, and accessible through a web browser. And heck, if I open-source it once it's in usable condition, maybe enough geeks will like it that it can gain some of those other features.