Note this from a post I made a few days back.
We looked into certifying non SxS cards for EX but the results were very poor; ranging from not meeting their own specs to taking a long while to do so….
Juan Martinez
Senior Manager Technology
Sony Electronics Inc.
That said, I know there are people experimenting with the EX1 WITH the 1.11 firmware upgrade. The reasoning being is that the firmware allows for USB ExpressCards because the PHU60K is actually a USB hard drive with SxS connection.
I’ve heard reports that someone got a Lexar 8GB card to record in SP mode but not HQ. There are questions of reliability too. I believe another person found issues after attempting to record after a couple of minutes.
If you’ve already updated to firmware 1.11 you might test but understand the risks involved if used for mission critical (paying) work.