Hi Will - Very cool! I’ve not heard of Great Plains before.
Some others that are worth checking out:
Plantd - a startup based in North Carolina creating board products (think OSB or MDF) from perennial grasses, and with an interesting local economic story in offering an alternative crop to multi-generational tobacco farmers.
TimberHP - a wood fiber insulation manufacturer based in Maine, aiming to offer board, batt, and fill products using softwood residuals from FSC forests.