Googling, I found Psism.
http://www.psism.com/reader.htm. Scroll about halfway down. The dedicated PC card readers are quite expensive. But if your cards are just storage, then you might be able to use the PC->CF adapter. (Same webpage, just above the PC card readers.) The webpage doesn't say OSX so probably best to call to be certain you don't have to install any drivers.
Viking used to make a USB PC card reader, but I believe it's been discontinued and their support website shows drivers only until 10.1.2.
Alternative perhaps is if your current device will work with SD cards in a PC card adapter. If so, then you convert to using SD cards, and use the built-in SD reader in the current Macbooks. (Or even CF cards in a PC card adapter, although you'd need a external CF card reader on the Mac. SD cards, you may be limited to 2GB or smaller if your device can't deal with SDHC.)
