Hi Ted,
I struggled with this concept myself... As technology changes and "improves", we (as consumers) feel as if we have to keep up. And if you search the archives, you'll see quite a few posts (some written by me) relative to upsampling and AVA DACs. In short, I have now come to the realization that it's a fruitless (albeit expensive) effort.
I stumbled upon a very strong paper (peer-reviewed research paper; citation available upon request) that tested standard redbook recordings (16 bit) w/ the latest and greatest 24 bit bla bla bla. The results were that people, regardless of the resolution of the system, could *not* tell the difference. The only time that differences could be detected were at unlistenable volumes. (In essence, the higher the bit rate, the lower the noise floor. But it's a moot point at normal listening levels.)
Frank was right all along; there's way more to a DAC than the actual D (digital). I would suspect that Frank's analog circuitry is what makes his DAC products so special. It's not the bit rate, upsampling, or other theoretical improvements--as they don't seem to carry over into real life.
Rather than chasing after the White Whale of bit-rate, I'd rather see increased product flexibility... Such as the ability to decode more digital file formats, rather than CDs alone.
