SxS transfer, will this work?
 

Siig USB to ExpressCard Adapter - 1 x ExpressCard/54 - JU-000012-S1 - Buy.com

the SIIG usb to expresscard adapter? I may get one anway to offload two cards
at once.

Probably won't work. The SXS cards require PCIe interface to work. One reason the Sony USB adapter is so large and expensive is that they have the PCIe to USB electronics in there. The SIIG device is only for USB based expresscards.

Scott, if your question is will this work with the (USB based) Kensington Expresscard /SDHC combo, there's a good chance it may.

If you buy it run the Crystal Disk Mark test on the Kensington / SDHC card (Ultra II, Extreme III, whatever you may own) in the SIIG.

This info WILL help us understand where the 8.3MB/s bottleneck is coming form using the Kensington / SDHC card. The Ultra II 15MB/s lives up to it's specs when tested with a standard SDHC reader, but based on calculations, it's only allowing 8.3MB/s when used in the EX. It sure would be nice to know if the EX is causing the bottleneck or is it the Kensington/SDHC card combo. Note: If you do buy it, if you can test it with the 16GB Ultra II 15MB/s, or the Extreme III 30MB/s SDHC. Some SDHC cards won't even meet the 5MB/s to run the EX HQ mode, the SanDisk Ultra II 15MB and their Extereme III 30MB/s easliy do.

As John mentioned it will not work with the SxS cards (PCIe based).