said by Time4aNAP :

Hey, I'm just going by the Rich Media article, that says "municipalities, tourism centers, small businesses and universities in North America". If that's in error, take it up with them.

That begs the question as to whether or not the cable plants have the power insertion capacity to handle the additional loads from these devices. After that, where do they place the radios, and the necessary antenna cluster? A lot of cable plants are buried. Those that aren't are typically leasing space on utility poles owned by the utilities that were there first.

Like the phone company.

I seriously doubt that AT&SBC, Qwest or Verizon will be magnanimous when their tenants/competition want to add the extra tonnage to their poles that will be required to support a workable WISP operation. And Cisco equipment is anything but inexpensive. One way or another, this is going to cost big money to build out.

Now it might seem to be a great choice for a cable company, with years of experience using coaxial cable for analog TV to keep on using it for data-only applications as well. After all, they have tons of the stuff, right? The thing is: cable companies have to buy that RG-6 just like everybody else. It's not free, and it's significantly more expensive per foot than CAT5-6 UTP.

I just don't see the limits of their existing physical plants falling neatly into the exact same spots where a Wi-Fi radio is needed. And the engineers and technicians who operate the current system will not automatically be competent to operate the WISP system just because it uses coax. Furthermore, 99% of DOCSIS is about keeping the customer from having any possibility of controlling their cable modem, which simply isn't an issue here. So I repeat, what's the advantage of the Cisco Aironet 1520?

For my money, a risky venture like this, competing with everyone including yourself, had better be done with a bare minimum capital outlay because it's bound to fail.

said by DaneJasper :

Both Cisco and Tropos are just too darned expensive, in my opinion.

As for feeding the upstream via DOCSIS, and competing with oneself and pole mounting, there might be some applications.

For example, a city owned municipal cable system which wants city-wide WiFi, and isn't concerned about the fact that it's competing with it's own cable Internet access. Perhaps they're charging something extra to use the WiFi, who knows.