I’m glad you mentioned the Mac aggregate device because it made me wonder if ASIO4ALL would do this on Windows. Trying it I don’t see why not. Install ASIO4ALL and select it in Wavelab, and it should see your USB DAC and ADC (if they are USB) and you can select their inputs and outputs in Wavelab. Without AES. The only downside (or maybe it’s not a downside if you record at source rate) compared to two computer pitch and catch is they have to run at the same rate (I think), and you probably have to clock the DAC from the ADC, or vice-versa.
Or maybe there’s a way to run two instances of Wavelab on one computer each with a different interface (and different rates?), but I think this way with ASIO4ALL would work too, at least for same rate stuff. I think.