> Isn't that the same card (the same Broadcom chipset) with the difference
> being just some additional, euro-asian channels in A1027?

I don't know the difference between the A1026 card and the A1027 card, but AirPort Extreme uses at least two different Broadcom chipsets (BCM4318 and BCM4320) which should both be supported. I remember I once read about the older BCM4306 being used for AirPort Extreme also, but I don't know how accurate this information was.