If they did, you'd have to buy a new Hip Zip to take advantage of it. The version you have only recognizes 40MB media.
Anyway, I have a 32MB Rio MP3 player, and to get around the memory size limit I reencoded select MP3's as mono. This cuts the file size in half--thus, doubling the player's capacity.
Stereo sound isn't that impressive on the train or walking outdoors, so it wasn't a big deal for me.
Just a thought.