The Peaberry is of a design that uses a mixer to convert the RF down to audio signals (I and Q), then processes it in the computer, and outputs it to the sound card.
The A to D conversion is done in the sound card chip, and I think its fixed in how it works.
In the setups where they do the A to D conversion at RF, I think they are limited in what chips are avalable (from the cell phone world), plus if you oversample, the cpu load goes way up in whatever is doing the processing.
I wonder where the tradeoff is between a 12 bit and 16 bit samples and oversample speeds...
If you want to listen to 30 MHz and have 4 samples, it has to run at 120 MHz sample rate...or is it 240 MHz?
To add to the situation, the pipe to move data in and out of the computer is a limitation with USB, less with firewire, and likely best with gig Ethernet.
You can increase the dynamic range of a system by oversampling and dithering even if the A/D does not have the dynamic range, this was used with radar 10 to 20 years ago when the best high speed A/D converters were 8 bits. Usually the signal riding on noise provides a natural dithering and the higher speed of the A/D provides for the oversampling or signal integration. When coherently integrating I and Q channels the noise is reduced by the square of the number of samples integrated. It really works.