I would agree. I only said tip stall as the LH wing dipped hard right at take off so that's what it looked like but having never experienced one I really wasn't sure. But I guess on a constant cord wing a tip stall isn't really possible. I'm leaning towards the root cause of the accident was from multiple reasons that compounded to cause the stall. First was the fact the grass on the runway was probably a bit too long for the little 40 sized Avistar. Another would be the prop size, and age of the prop. It had some pretty heavy build up of grass on it that could easily make it less efficient. Lastly, as I was removing the wire landing gear to convert to a tail dragger I noticed the LH wheel was extremely hard to roll. It wasn't completely locked up but pretty dang close. I never really noticed it but lesson learned to check main wheels before I take it down the runway. That had to have added to the take off roll as well.

That said the Avistar is a semi-sym wing is it not?