It will work with any Garmin card. You're just using the case not the board/ chipset. I've ordered the 2G chip, waiting for it to arrive. A fellow inmate was gracious enough to give me a dead 32M card he had so I can used the case from it. Once the chip gets here, i'll put it all together and pop it in and see how well it works.
On another note. What's to stop us from just installing the 2G chipset and using some thin foam to support it in the GPS unit? Seems like that should work and save us from having to buy a Garmin card for the case or gut a good card for the upgrade.