So it looks like the Gunslingers are using the following phono preamps with an ADC and USB output:

NAD PP-3 at $200 retail and regularly available for $179
Behringer UFO202 at $45 retail

There are a couple of others, one mentioned here:
Rolls/Bellari VP-530 at $400
Audio Genie Pro at $70 but their website says the item is discontinued but it seems to be available from online retailers.

There is also the Pro-Ject II USB for $200 online and BestBuy.

I've not seen any side-by-side comparisons between any of these preamps with usb. Anybody else seen a comparison or made one themselves? One of the issues I'm trying to figure out is each ADC's sample rate.