I've posted this elsewhere (on the hot hod server topic) but I think it's better to create a topic for it because I've gathered more info about it.

Adrian

Coming soon ….

tX-USBexp

Ultimate USB Audio Performance

PCI express USB 3.0 Host Card

tX-USB exp is PCI express USB 3.0 host card that enables upgrade of USB audio performance of standard PC to High-End grade. 
- More advanced PC power supply ripple noise filter & RF noise filter performance.
- Ultra Low Noise Linear regulator circuit is used in all circuit to minimize the noise. 
- USB port power on/off function. 

Product Specifications 
- PCI express x1 Gen 2 interface
- Support super-speed, high-speed, full-speed, and low-speed

- Power input
Select power source automatically (external first, internal).
Internal power : 
IDE 4 pin PC power connector
Input voltage : +12.0V(+0.5V, -0.5V)
External power :
Standard DC power Input jack
Input voltage : +6.4V ~ 9Vdc
Input current : 2.5A max

- USB port power
Output voltage : +5.0V(+0.5V, -0.25V)
Output Current : 1.0A max
Over current protection : 1.5A at 20°C 

- Operating invironment
Operating temperature : 0°C ~ 40°C
Storage temperature : -10°C ~ 50°C
Operating & storage humidity : 10% ~ 90%

- OS support
Windows 7
OS-X v10.x
Linux

Here:

http://www.sotm-audio.com/products7.php

this is the same info that I copied and paste…

I didn't find it anywhere for sale yet…

Adrian