Anyone using Antelope Audio interfaces?

Fleer
Those Thunderbolt 3 and USB 3.1 protocols, often over USB-C, may do away with latency altogether. Here's looking at Apogee and maybe UA for future developments. Who knows, half a year from now. 

Keep in mind that Thunderbolt (with full "PCIe via Thunderbolt" drivers/support) will offer performance on par with PCIe.  
It will not surpass PCIe performance.
 
Another thing to keep in mind:
The amount of I/O being discussed here is nowhere close to saturating the USB-2 bus.
Simply throwing additional unused bandwidth at the situation isn't going to increase performance.
 
We've got the PCIe bus:
PC hardware and the OS are ultimately going to determine just how low you can take round-trip latency.  

• USB2:  The Fireface UFX yields 4ms total round-trip latency at a 48-sample ASIO buffer size 48k
• PCIe/Thunderbolt:  At a 32-sample ASIO buffer size 48k, you're right around the 3ms mark

That's as good as it gets (at least for the next several years) until the PCIe bus and OS are superseded.  
 
RME, MOTU, and Lynx all have PCIe audio interfaces that provide a 32-Sample ASIO buffer size.
 

http://www.sweetwater.com...vvu3ztACFYKBaQoduGcNNA