If you have 1 hddvr, and a hd box in another room, you can do everything on that hd box that you can do on the hddvr box, except pause live tv.
So, if you had more then one hd box, you could do that in those rooms as well. You can also have more then one hddvr box and so on.
keep in mind, you get 1 hddvr and 1hd box for free with the current promotion, anything more then that, you would have to pay for. you could get 2 standard def boxes for free also with that offer.
There is a workaround to the inability to pause live TV on the H24. Record the program you are watching on the H24 (you can select the DVR you want to record to). Then start playback. You can pause all you want. I do it all the time with my H24.