A cheap One For All or Radio Shack remote would serve your purpose, except for the fact that the macros would have to go on a button other than the device buttons (ie, the button labelled DVD, etc).

However, if you are prepared to put a little effort into this, I would recommend getting the $30 8 device Radio Shack 15-2116 remote and a $15 JP1 cable. With JP1 you can put macros on the device buttons. You could then do all the hard work yourself programming the macros, etc for you folks.

The other added advantage of using JP1 is, if you folks need their remote re-programmed and they have the JP1 cable, you can do the programming at your place and send them the new programming by email. This is what I do with my father in law and his RS 15-1994 remote.

Here's where you can get a JP1 cable for $15 shipped (till father's day)...
http://www.hovisdirect.com

Rob
http://www.hifi-remote.com