What about the g400 did you find unplayable? Mine worked fine on my shidenkai.

Switched to a g100s though for lower weight, and replaced the mouse feet for even smoother ones, works well with the pad.

I get plenty of negative accel, basically any quick swpie for ~6cm makes it go crazy.Do you have the white shidenkai or the red one?

I've tried the Shiden Snow White, and the only mouse that worked on it was the G502 (with surface calibration). Salmosa, MS 1.1 and Kana V2 had some sort of problem with it. (negaccel and some cursor jump here and there) Haven't tried the red one BTW.
Sent back the mouse pad to the original owner, and I'm sticking with the Talent for life. :D
(I haven't tried my MX518 on the Shiden extensively, so I cant say anything 'bout that.)
The fact is, infrared Razers hate this pad.

g400's don't inherently get neg. accel. Sounds to me like your pad is the problem, maybe the white refracts too much light or something.

As far as I'm aware, Artisan don't make a white shidenkai: only red or orange. The white one is the shiden. I have the orange shidenkai and every mouse I've tried works fine on it.

Try your mice on different pads to see if you still get the same problem.

I dont get negative accel on any other pad, that's why i asked specifically about the shiden. Do you have the g400 version with or without prediction?

Ok.

Without.

If you can I recommend swapping the white shiden for an orange shidenkai.

I had same with my old DA 3G :)

Awesome DA replacement for you will be Coolermaster Alcor

alcor on white shiden: http://i.imgur.com/M0lSSqh.png
g400 on same pad: http://i.imgur.com/aHJkisp.png

Do you know if the g400s works any better then the regular g400?
How about the zowie mice?

zowie am(modded with IR-LED tho): http://i.imgur.com/8nDiHVA.png
don't know about the g400s.