Now that I'm getting on with the Fizzer I figure it's a good time to throw a wrench into the works. I want to try GP shift, but there isn't enough room to flip the knuckle thanks to the sprocket cover. I'm thinking a nice shift lever attached directly to the shift shaft, ditching the linkage setup entirely should do the trick. Anyone gone down this road, or have a pointer on how to go GP on these machines?

Usually its done by the rear set, instead of the shift rod going below the pedal it goes above ... You need a pedal with the linkage above or rotated and/or a different length rod

This is a common mod on Fzr 600s.
Use a FJ1200 gearchange shaft knuckle to reverse the pattern and provide casing clearance.
Use a SV650 gearchange rod for adjustment, if you do not have the benefits of a resident http://www.projection-components.co.uk/ fabrication shop.

I see no reason for this set up not to be applied to the 400.

I believe simply modding a gear pedal and reversing/shortening it leads to insufficient leverage and one has to stomp on the pedal and downchanges are slower.

Changing over mid season may provide some entertaining/expensive moments , especially in a "competitive" moment; do keep us informed.

Fortunately I have a slipper and have tested panic excessive downshifting already. :D

I'm not shifting enough as it is on track, so I've got plenty of time to contemplate exactly what my foot needs to be doing. I'm hoping GP shift will make it easier to grab upshifts cranked over and hauling to the right up hill under throttle. I'm just not comfy with that shift and loosing a ton of time there.