Thanks for all the info. There is a guy selling a Handsome XOXO frame on one of the local CL's. He claims that 2.4 tires won't fit, although they'd be close. I think I will go check it out.

An old school MTB, with lightweight steel and a high-rake fork would also work out well for a 26" wheel build. I'll keep my eye open. I would also really like to find a lightweight, mid-balance platform for the 29x2.4 Super Moto. Something like the Singular Gryphon in a lighter weight steel.

Thank you for the ideas.