AFAIK, switching ISPs is the only way to do it. I would call your ISP and complain to them that you are paying for that connection and you want the full bandwidth. If they tell you that you can't have the full bandwidth, tell them you will be switching to another ISP that does not do this. If enough people leave the predatory ISPs then things will change.

One thing to note is that if your ISP is a provider of connectivity via a wireless connection (not the EVDO or UMTS kind), then they may have bandwidth throttling and for good reason. The wireless bandwidth is shared by all the users on the node and if one user has the full bandwidth, it prevents others from utilizing it. But this sort of policy should be well published by the ISP.

Slinging with a SlingCatcher, a ProHD, a Pro, a Solo, an AV, and a Slingbox Classic. 3 Replay TV units, a Roku Photobridge and a Roku M2000 Soundbridge, an AppleTV, a Vudu, and digital cable. www.na9d.net

It may not be traffic shaping, but packet prioritizing.  I wonder if Sling traffic has any unique markers that a company like Sandvine could use to delay traffic like they are doing with Bittorrent.