Most of the boards using VIA chipsets that I've tried still seem to support 2 drives, and it has been mainly the Intel and nForce boards that are limited to 1. It's good to hear that the newer nForce boards could be fine again too.
My Intel D875PBZ only supports 1 drive, and some newer Intel boards I checked also only mention "a single floppy drive" in their online manuals. So there's probably not much hope for those in the future.
Checking the BIOS is the best indicator of whether 2 drives are supported. BIOSes that list only A: are normally using a cut-down floppy controller that doesn't have B: physically connected, so there's no way to use it for adfread.