'Private' Marketplace sections
If not is this kind of private space something worth considering, even for a small monthly diskspace rental?
For 5.7/5.8 I have my own toolset that includes similar functionality, but its very specific to the way I work so no use to others.
I think Remo has a similar 5.7 utility somewhere on github if you search for it.
Devops have indicated they could provide a script which could allow a zip uploaded and unpacked to /packages dir which would be good, too. Defo need some sort of fallback though, in case!