In this model, it seems you assuming that the wireless access points are arranged in a strict hierarchy, based on locality. Does it follow, then, that your model assumes that wireless mesh access points would then connect to a single wlan to lan bridge (not so ad hoc anymore)? This seems to be the take Cisco is using for their Aeronet 1500 series mesh offering.
My question is, wouldn't aggregate bandwidth increase considerably if there were an even mix of strict wlan routers in addition to wired routers which could also function as wireless access points? In that scenario, since the 'top' end is in fact many different routers instead of just one large scale router, would not that effectively reduce the distance for anyone in terms of wireless hops? Furthermore, what about nonstandard routing algorithms which allow for multiple simultaneous paths based on demand? E.g. low priority transmissions (say ones that require a limited threshold of bandwidth, say like one a hand-held e-mail device might use) could be directed over longer paths to allow more demanding transmissions to take a shorter route?
I'm throwing this out there strictly from the position of network theory, but I can't see why such a solution isn't feasible, at least conceptually.