Could I build such a board?
Maybe, but it would suck snd be a lot of effort I think.
Easier to put a gopro facing up in 3 feet of water and shoot kitesurfboards, twintips, raceboards going back and forth over it I think....
If domeone is kind enough to donate to me a new surfboard (firewire 6-2 sub scorcher please ) snd a raceboard, better yet an airush sector, v3 (54cm), I will volunteer to do this experiment!

Actually, just ride or watch other kiters closely, you will see how it is.

Toe in and cant reduce drag.

kite boards outpoint direction of travel (toe compensates) and are almost always on edge (cant compensates)

I toe in my 2 degrees on my custom TT and its still not the perfect angle 3-4 would be better, but my fins are tiny so it doesnt matter that much to me.

cant say much about racing though. I know most wave boards its preferred to reduce the standard angles from the surfing world cause they create too much drag and feels slow. Compensation with the relation between fore and aft fins and fin location relative to edge and tail accommodates reduced angle

Good discussion............. I think to a large degree shore break wave riding probably doesn't need good fin performance as evidenced by guys riding skim boards with NO fins at all.......... I'm referring to all other types of riding conditions, open ocean swell, bay and river riding. I know wave riders want slow boards so I'm assuming toe-in was invented to act as brakes so it's good for those conditions, but nothing else !

Sorry, but this is not a good assumption.
It's about the flow of the water under the board.
When a board makes leeway, toe-in reduces drag.
When a board is heeled, cant maximizes lift.
Compare to racing yachts, specifically the open class ocean racers.
They have toed-in and canted daggerboards.
This is not to create drag.
Interestingly, these yachts have the flat side of their daggerboard foils to the outside,rather than the inside as on boards. This is because they heel to leeward, not to windward like a board does.
In both cases, the design is about how water actually flows around the foils, not how we think of ourselves as "going in a straight line," or "trying to stay in the pit, etc.
Watch some riders, or videos, pay attention to leeway angle and edging, it will open your eyes...

Well BWD you make a good case. I could be wrong about my assumptions, that's kinda why I started this thread asking if anyone ever rode two similer boards, one with toe-in and one without. Thanks for the discussion.............