We have reported on a lot of HTPC keyboards like the Koribo Leira and that one Samsung one for Smart TVs. Here is the MIX Wireless Mini HTPC Keyboard Mouse, which is a palm-sized device that is a 2.4 GHz RF wireless keyboard.
There is no trackball on this thing, but it has an optical touchpad which allows the user to interact with the operating system within a 7 to 10 meter range.
It does require batteries to operate or possibly a USB charge, but it only weighs in at about 93 grams.
In short, it is something that fits nice on your living room table so you can program all sorts of things on your home theater. As for the cost, we are talking of a price range of about $50, and I will leave you to decide if this is a fair price for an HTPC remote. I believe that you can head over to the Brando site to get it.