Niche industry: data on multiples and smaller target companies

Hi all, I'm searching for a company in the professional audio and music products industry, where I've spent my 20-year career. I have a very strong network of connections within the industry and significant operating experience.

1. There are few publicly traded companies, so virtually all deal information seems not to be disclosed. There's little to nothing relevant available in BVR as far as I can tell. How do folks find information on past deals—and particularly multiples—in situations like this?

2. There's little analyst coverage of the industry, and what's covered in IBIS is dated and incomplete based on my knowledge of the industry. The data I was able to find from a trade publication covers only the top 225 companies by revenue, cutting off at $10M. The publisher stated they don't collect data on smaller companies when I asked. I've also tried messaging the trade association, but have gotten no response despite several attempts. The industry’s primary trade show had 1,600 booths representing more than 3,500 brands this year, suggesting that there may be more than 3,000 companies with revenues below $10 million. Has anyone dealt with a situation like this and how did you pursue data on smaller players?