FWIW I think poplar is what Slingshot uses in their TT boards (some at least),
combined with (?)corecell (or similar color foam at least).
The wood is in wide stringers, take up around 30-50% of the width between the feet, I saw it in one of the cut in half boards displayed at the local megakitemart.
...so probably a good option if you are in the USA, available and not too pricy.
i'm in the eu, poplar is cheap here as well.
seems like the only disadvantage poplar has is wrapping when not very well dried as dr.lojz pointed out:
this wood is growing the best on the relative high humidity areas
and must to be proper dryed
everybody i asked agreed on that.
the foam-wood combo you describe, being light and strong is probably the best option.
but shaping a core made of two so very different in terms of hardness materials, doesn't sound a easy task for my skills. i ll try that for sure in the future.
I saw the thead with pics of your board,
i really liked the simple way you glass it with no vacuum / no rckr table etc.
thanx for the input guys