It's interesting you mention that. Here's another way of looking at this....from the Sirius vantage point. Big 10 was part of Best of XM for Sirius subscribers last year. However, go to the College Sports page at Sirius' website and it says this: "In addition to the all the live college football, basketball, baseball and other sports already broadcast on SIRIUS, top college conferences like the Pac-10, Big 12, Big East, SEC and the ACC are now available to SIRIUS subscribers as part of The Best of XM." As you may notice, it lists all of the BCS conferences, but one.
Or if you go to the Best of XM page at the Sirius website, it says this for College Sports: "Games from the top college conferences, including Pac-10, Big 12, Big East, ACC and SEC." Again, a particular conference isn't mentioned.
Something else worth noting is on XM's website, and if you go to their sports page, and where they have the logos for Mad Dog Radio, NFL, MLB, etc. if you click that arrow on the right, it shows all the logos of the BCS conferences, except for the Big 10's.