While there is no difference from a technology perspective, there's also no benefit to be gained by interconnecting large networks at a public (as opposed to private) interconnects.

Sure there is. Running one larger interconnect has the potential to be much less expensive and easier to run than many smaller ones. Economy of scale... That's simply a fallacy. One larger interconnect assumes that the cost of aggregate bandwidth scales linearly, when it fact it's clearly super-linear and may well be exponential. This becomes worse as supporting the aggregate bandwidth exceeds commodity media technology. Tony