The following discussion of the KX3 was harvested from an on-air round-table shortly after Dayton.
The KX3 is definitely a software defined radio with knobs. Wayne/N6KR talks about this at approximately +3.20 into his demo. He also discusses the “roofing filters” at approximately +4.10 into his demo. Since the KX3 is indeed a ‘true SDR’ (i.e., direct-conversion receiver using Quadrature Sampling Detector to derive I and Q baseband signals for processing by a DSP chip/firmware), the “roofing filters’ option (as I understand it) will be baseband (audio-frequency) filters. Also note that the I and Q signals are being made available for processing externally by a computer sound card if one wanted to do that. A serial interface (lower power requirement than USB) will also be available for computer control (if desired). But a computer is definitely not required for the KX3 to fully function as a stand-alone radio. More here.
A couple of additional links you might find interesting are:
http://www.ww2pt.com/2011/05/
http://www.radiocronache.com/
It seems that about the only thing we don’t know now is the price… that and who amongst us is going to order one first.