Class D amps w/ digital inputs?

Doesn't the new NAD integrated have a digital input?

Are you assuming that "Class D" is "digital? "Class D" is an analog design and application. Tact uses DACs, as well as some custom DSP programming, so it's more than just a "digital amp".

The Bel Canto S300i has digital input options.

NAD is sort of a variable gain DAC with hi power outputs......though it can be used as a 'simple' power amp. A lot going on here, so have a read.

http://stereophile.com/solidpoweramps/nad_m2_direct_digital_integrated_amplifier/

Bel Canto S300id
Wadia PowerDac
Firestone Ruby