My startup concept has been verbally validated by a number of thought-leaders whose companies plan to buy my services when my venture hits a certain scale. As I'm operating in a niche space that typical VC/startup investors are unfamiliar with, I'd like to get these thought leaders to express their interest in a non-binding LOI that I can present to investors.
I'm assuming this might be an atypical approach as my startup-in-a-box attorneys do not have a template for me to use. At the same time, I don't see an alternative given how specialized the field is. Does anyone have a suggestion on a template?
I believe what you are looking for is a Letter of Support.
Letter of Intent is a normal mode of business for startups to raise money from investors. There are several free templates available on the Internet -- just search for it!
I believe you're on the right track. You may need to create your own customised document inform of support, recommendation and investment intent letter. I suggest you sit down with your lawyer and together you guys can draft a suitable document.