That where Energy Network comes in.

Is there a DIY compact type of insulation that would work? 

It will be hard to raise 400k in pure private money unless you have a large network of private investors.

There is a great Investor Network here to aide your growth, best of luck!

We have a 100 y/o single family buy&hold in Missouri and would like to turn the attic into usable space. ideally we could keep the rafters exposed in keeping with the character of the home, so the standard 6 inch fiberglass would not work.Is there a DIY compact type of insulation that would work? 

Keep educating yourself and also start networking with like-minded investors to move your process further along. 

Condensing a large project in half as a DIY beaver that likes to build his OWN dam is not recommended. 

I haven’t exactly found the area I want to invest so I’m open to all recommendations.ANYONE interested in talking more please comment with any questions I can answer to help find the best path to go let me know If anyone is interested in getting lunch in or around the Camillus/Syracuse New York area please let me know( again I’ll pay 😀) just looking for a little bit of your time and who knows I could be a great add to your network

I’m also building my network so I can do deals outside of my market.

Still, if you are going to invest up north, I firmly believe you'll enjoy the most success if you avoid newer construction and try to get into deals that need at least some rehab, assuming you can build a good network of construction folks.