I did the monthly channel scan, and everything is status quo in terms of what channels are on what transponders. But the removal of the ESPN alternates last week got me thinking... 144, 145, 146, 147, and 148 are all free (although I do know 148 is sometimes used for a mirror of TrvTV during the mens basketball tournament)
We know that PAC12 Network is done with live sporting events, and is shutting down on June 30, so 409 (both SD and HD versions) are going to be removed as well as the alternates of 592, 593, 594, 595. (Channel 406 for non VIP receivers). Longhorn Network is also done with live events, although no firm date has been release, is rumored to be shutting down on July 1 when Texas moves to the SEC and the Longhorn Network content gets added to SEC Network. That means 407 is going to be free.
Part of me wonders if Dish is going to move ACC Network and SEC Network from the 402/404 area down to 144/145 so all the ESPN channels are right next to each other, and then move Big 10 Network to 148 next to FS1 and FS2. There is so much cross promotion between ESPN/ESPN2/ESPNU/ACCN/SEC channels during college football season as well as FOX/FS1/FS2/Big10, it wouldn't surprise me if they are moved to a similar area by the time college football rolls around. Back when Big10 Network was first put up in the 400's, it was treated as an RSN with all the other RSN's, and only available in the areas with a Big10 school. But now that it is a national channel, along with ACC Network and SEC Network, it would make sense for them to be with the other sports channels.