I'd like to see some high-end stuff with specs centered more around low impedance headphones. Most of the top headphones are now low impedance. There's the Edition 9, GS1000, DX1000, W5000, AH-D5000, etc. None of them are high-z, which, from what I've heard, is the style of headphone that works best with your amps. It'd even be great if you could tune amps for specific headphones. An Edition 9-specific amp, a GS1000-specific amp, etc. If you used tubes, you could choose by ear the best tubes for a particular set of headphones. If the amp is solid-state, you could choose the spec that objectively does the best job with the load that a particular headphone offers.
I would also love to see options for higher-end DACs, and some way of connecting it to a computer that doesn't induce a lot of jitter like USB, and that allows for 24/96 transfer, so that one could use his computer as a transport without degraded sound quality. Perhaps something like Empirical Audio's modified Transit with I2S output, but built into the amp/DAC. I don't know if PCI would make for better performance than USB, but if so then I'd be happy to connect the DAC to my computer with that method. If I'm paying thousands of dollars for good sound quality, then I'm certainly willing to endure a little inconvenience, such as having to use a PCI output instead of a USB or needing to install software on my computer, or even needing to change my music server, to get it.
By the way, I love your crossfeed and think further developing that would be a great investment. I heard my Edition 9 with a maxed out 2007 Home a few weeks ago, and it sounded great with the crossfeed and the first brightness filter turned on.
Finally, I'd love to see a new, more intelligent standard for connecting balanced headphones to amps; perhaps a type of plug that can also connect to standard 1/4" jacks. Maybe you could add a 4th conductor to a 1/4" plug, and make it a little longer so that the last conductor sticks out when it's plugged into a standard 1/4" jack. The two ground channels could be merged until the plug is inserted into a balanced jack, which is a bit deeper than the standard unbalanced jack. The balanced jack could actuate a switch in the plug that would separate the two ground channels. All in all, it would be more convenient because headphones could be used both balanced and unbalanced without an adaptor, and it would take up less internal space; and it might even be cheaper. If there's no interest in this, an option for a 4-pin XLR jack would be nice. This could save space in the balanced desktop (and maybe make room for a brightness filter?).
At least I get the Wadia.
