Look at the hardware you want and ask them the native Linux driver. Really, they are the only one who can really provide them for you. Let them know why you passed on their hardware.
Other than that, look at chipset they built in the wifi card (I know it really is a bitch if not impossible) and hunt the driver for it before you buy it. Even than, it's not guarrantie. When I bought my netgear card, everyone was talking about how it was supported. But Netgear changed the chipset with v3 which I bought and it wasn't supported so I was stuck with ndiswrapper.
I don't know of any one who keep track of drivers for wifi cards though. Sorry.