Hey Sam,
Greetings, but hey - who am I to say that - 1st post for me as well :glasses10: !
I don't know of anyone who will do a body on a neck-through blank without finishing the whole guitar for you, but I've got half decent woodworking skills/tools, and have also thought of making a neck-thru at times as well. I know that Carvin offers a reasonably-priced blank ($209), and have considered ordering one to give it a whirl:
https://www.carvinguitars.com/products/single.php?product=NT6
Unfortunately, Warmoth doesn't do these (yet?), but maybe this is a place to start... hope it helps...
John