I came across Sei Basses purely by accident. A few years back I was looking for a six to replace a Smith six that was just too head-heavy. I saw a headless Sei six on EBay that was here in the states, bought it, and was hooked. It is S/N 053 and very sweet.
And after visiting the shop earlier this year to work out details on my new Millennium-7 I'm even more pleased with what Martin and the gang are doing.
I sold S/N 006 a few months back on EBay. You may have seen it; a fretless, headless six with Thuya front and back and wenge center. I loved it except the "fret" LEDs were positioned as they would be for a fretted bass instead of a fretless...i.e. not on the "frets" themselves but in between. I've played a pre-Gibson fretless Tobias-5 for years with the markers in the normal fretless place and I just couldn't break my old habit.
Hey Sparks! Great to see you on here. Been a while since we touched bass...PI. I love "Motel Boy" on your myspace...who is that bass player anyway????

) "Reduced" has a great "Lamb Lies Down On Broadway" feel -- very nice.
Here's an URL to some photos of my Sei's:
http://s200.photobucket.com/albums/aa46/kac123456/?
Cheers!