This morning we broke the news that Comcast will no longer be offering Pivot wireless service with Sprint. GigaOM has learned that one reason for the move (aside from the fact nobody was buying it) is that Comcast is busy building their own wireless division, which would clearly make the Pivot effort redundant. Comcast has apparently hired former CTO of Telefonica O2 Europe, Dave Williams, as the unit’s CTO.

Comcast was a no show last month when an expected plan to fund Sprint's Xohm service never materialized. Comcast CEO Brian Roberts has also traditionally proclaimed that he doesn't think the quadruple play (adding wireless to VoIP, data and video) would work. Meanwhile, Comcast stock has taken a beating the last few years by investors who were afraid that a massive wireless expenditure was on the horizon.

In other words, there's a lot of unanswered questions here still. Comcast could be creating a mobile WiMax Xohm-reseller (most likely). They could be preparing a buyout of another wireless carrier. They could be just starting the long road of building their own wireless network from scratch (probably the least likely). We'd ask Comcast insiders to keep their ear to the ground over the next several months and drop us a line should they hear more.