The plug size is different from most I've seen in stores.  I've always wondered if you could just buy a new one and cut and splice to the old plug.  It should work.  It's been talked about here quite a bit.  A few people have gotten free ones from Sling by calling tech support.  I don't think they've got it on their web store.

Slinging Tivo Series 2, Tivo HD, and TW cable from a Pro. Slinging Tivo HD from a Solo, Slinging Humax DRT800, and TW cable from a Classic to Sprint Mogul, AT&T SX66, N62, 8525, and Dell Inspiron 8600 with Sprint EVDO over Windstream DSL.

amdade said: Thanks Ryan, Tech support helped, new one on the way, its a very difficult item to find in the stores.... I looked and failed... good idea put these up for sale on the site.. 

HI ALL,

I AM ALSO Searching for SLING IR BLASTER please help me where can I get it.

 Thanks