WTB chassis flat pack or blueprints

Hi everyone, I want to start cratch build. I have been building locost's, retoring and restomoding variuos cars. So I'm pretty konfident in my self, but I dont have where to start from. Thought about buying gtforte flat pack, but after reading about him I consider its not an aption.
Maybe someone in this forum can sell blueprints or chassis pre cut flat pack.
Thank you.
Sorry if my English is bad, I'm from Lithuania.