I've had good luck buying used replacement remotes for 3 different DVD recorders (2 Panasonics and a Toshiba), via Ebay and one of the remote resellers on the web. They were each around 20 bucks and all work perfectly.
I've also programmed a new universal remote to work with my Sharp recorder, and it's OK for the basic functions. The problem arises when I want to set it up for timed recording. The buttons I need for some functions just aren't there on a universal.