Actually, the laminate testing isn't terribly bad if you know where to go. We have a local lab we send a lot of work out to that is VERY reasonable when it comes to materials testing. You have to have the materials knowledge to put together a good B-Basis test plan, but it's not that far out of the realm for a designer to do this. Additionally, Bob H makes a great point below that basing your design allowables on a strain limit versus a stress limit is usually a more acceptable design theory for both thermoset and thermoplastic composites.
Working with a knowledgeable engineer well versed in the materials you are designing with is key. Given the breadth of experience within EAA, I just don't think this qualifies as "out of reach" for homebuilt aircraft designers or builders. This is really where the EAA Technical Counselor program should shine.