Good idea on mainboard - I do have an old ASUS P4 board here I can hack up. I'll check that out today. Right now I have to go into town for something, so it'll be a few hours.
If you don't find anything suitable on that mainboard and think I can be of assistance again, let me know:
http://www.maritex.com.pl/pl/shop/products/ggid/15955Thanks for the offer. It's mostly the time that is an issue.
**** NEW FLASH ****I was busy with other commitments most of today, but I'm just getting back to it.
Here's an interesting data point:
If I hook up my USB via a cheap pocket hub to my notebook the error rate drops right off to < 1% (short test so far). So there's a quick fix for those wanting to see if the USB noise is causing the error issues.
My guess is that the hub has correct EMI filtering beads on it's connections and acts as the filter we need.
Looking at this now - EMI2121
http://www.onsemi.com/pub_link/Collateral/EMI2121MT-D.PDF