I know, weird thing to ask for...
And I totally understand if you don't like the cut steam takes for its distribution and maybe some of their contract details don't mesh with what you need. But if Steam is out of the question for any reason, maybe you could make your installs similar to XLN's online installer, which is a little bit like Steam...
So, why am I even asking? Several reasons:
1) Over the versions, you keep changing the 3rd party tools supplied. So installing Sonar after you had to wipe windows once again, or just cause you have a new hard drive or computer, which ends up happening way more often than I'd like, becomes a major undertaking, as you have to basically install every previous version of Sonar if you want some of the filters or synths they came with. If there was an XLN alike online installer, where you can pick what you want to install from a list of all products you own, it would be a lot less of a headache...
2) Just because optional automated installs and updates are really nice.
3) It could also function like Windows system file checker, automatically checking, updating and repairing corrupted or outdated files when we have problems.
4) We're not allowed to transfer (sell, gift) the software anyway, so having it registered to one's Steam account wouldn't have any negatives for Cakewalk users, none that I can think of, anyway...