Don-
I don't mean to sound negative. You're a very nice guy, and to have Thomas as a friend (and backer of your system) is a real plus. The design is very cool, and it does work as described. I played your personal guitar- the one with the GK unit- at NAMM. The trem is very, very smooth.
Since you asked, here goes:
1. MASSIVE modifications necessary to the guitar body.
This was stated by you at the show, in your posts on forums online, and on your website. At the show you also said that you were the only one thus far that could properly install one, and that it was a very complex process to retro-fit the trem into a guitar.
2. Intonation issues.
When a fulcrum trem (vintage-type, Floyd, etc.) drops the string pitch, it travels in an arc. This gives the strings a little distance to maintain intonation before it is lost.
With your system and it's method of travel, intonation is lost immediately. Both when lowering pitch and raising it.
3. Exorbitant production costs.
Considering the necessary components, materials, and machine work, even if production was done overseas, you're looking at a $300-400 per unit cost. That would put MSRP somewhere between $900-1200. Plus shipping.
For a trem.
One that doesn't just drop in.
4. Strings break. They always have and they always will.
Claiming that a tremolo/vibrato system won't break strings is hopeful, at best.
I only posed the question because the members here are pretty good at figuring out problems and coming up with working solutions. It was an effort to not only address the issues with your system, but also present you with some possible ideas on correcting them...from 5000+ pretty cool and very smart members.
I am *not* a nay-sayer. As I stated above, I like the design and the unit feels nice.
What I am is realistic. While the Space Shuttle is a great way to travel, it doesn't work well for trips to the grocery store.