Yeah, the simple tiling would definitely reduce data needed and make it seem less like it was trying to compete with face time or skype VM, or what have you. Preserving the beautiful simplicity is pretty important to me. I may have the server space necessary for this. Here's the crucial question: let's say I put this together and a million people start using it (good kinda problem). How would I make the project sustainable in terms of cost of data storage/transfer in a task/service which can and should be free? This is the conundrum I can't quite wrap my head around. Perhaps I should start building, and see if the kinks can be worked out as I go.
The way you could do this is putting non-intrusive ads on the site and/or setting up an account for donations. These are the two ways that would keep the simplicity and create revenue. Your web host may allow upgrading your plan by buying more disk space and/or bandwidth is needed. Who do you use?