"Can I sell an HR20?"
Sure, see below.
1) Make it look like you are selling it , but in fact you are leasing it, right?
2) Put it in very small writing on the box - or better yet, don't put it anywhere at all - that you are in fact leasing it.
3) Don't let the buyer know that when he purchases it, he is comitting to a two year contract. Keep that fact inconspicuous.
4) But once you've got your mark to lease it and enter into a two year committment contract, change the contract so you can now charge your mark more to get the same high definition channels he got when he bought - no scratch "bought" - "leased" it. You do this by just calling his package a different name and then charge for that other name.
5) Once you've done all this - if your buyer has problems with the unit, send him an older refurbished unit as a replacement and start his two year committment all over again. (Oh yeah, if his original had the antenna built in, send him one without the antenna so he'll have to purchase an antenna too to get what he had.)
6) Now you've done it. Feel good?