@jdaviescoates Great idea! I'd definitely love to be a part of something like that.
What I do:
I do freelance web & tech services as a side business, and that includes hosting a bunch of things for customers which I do on Cloudron. Specifically WordPress websites for roughly 15 clients, and recently even some SFTP servers for one client too. Also a nodeBB forum for a client, Bitwarden password manager, email hosting of course, webmail apps, all that jazz. WordPress and email is the vast majority of what I host for my clients, but I get to dabble in other areas too which I like. Oh and web analytics too of course as that's bundled with my web hosting plan I sell to them, and to my surprise many of them actually really like seeing the emailed report from Matomo where they see all the results from each city, country, dates and times of busy traffic, etc. When I started offering it I honestly didn't think too many people would care, but most of them really like that part. I guess it sort of helps justify to them why they have a website in the first place so they can see how many people they're effectively reaching and such too in one area.
I don't necessarily market my services as a Saas-Cloudron or anything like that, just to be clear in case that's kind of what you were asking earlier, but I am very open in spreading the word of Cloudron (sounds like I'm in a cult, lol) to any of my clients that want to learn more about how I manage things, and even link to Cloudron from my website, so generally the customers that actually care to know that stuff all know I'm using Cloudron as the platform for everything. 
Quick side story about the SFTP server I recently setup, just because I think it's really cool, haha:
Using Surfer, I setup an SFTP server to bridge a medical clinic (client of mine) administering COVID-19 tests and the lab they hired to actually process the tests. Before, they were emailing constantly between clinic and lab and it was a hassle for them to keep track of everything... and we later found out that the lab they contracted actually had a script which they use for their larger clients I guess - it polls the SFTP server every 5 minutes for a CSV file which the clinic fills it out and saves to the SFTP server for each patient, each patient being it's own row on the CSV. It's streamlined their entire process now - just that one thing alone - to the point where they get their results much faster now from the lab and can then forward that to the patients much quicker than before as it's way less overhead in communications between the lab and clinic. Once I heard about this and set it up for them and learned how much better it made things for them, honestly I was humbled in a way, I consider myself fortunate to have been a very very very tiny part of that process to ensure people can get their COVID-19 test results sooner. It really wasn't much work on my part at all, Cloudron made it easy to implement! It was still cool to be a part of an improvement to this essential service in my region none-the-less.
Sorry I'm rambling on now, lol, the answer to your original question is "Yes, I offer services to my clients that I host using Cloudron".
haha.