I'm currently in the role of a GIS service provider for a utility, and as part of that role we post the sub-parent version to 'SDE.Default' (which is in 'Protected' status) using the 'sde' user on a daily basis. Our client likes the fact that SDE.Default is 'Protected', as it prevents any inadvertent edits, but they would also like the ability for some of their super-users to post to 'Default' themselves, instead of having to contact us for that task. Versioning permissions is preventing us from doing this, as we cannot disclose the 'sde' credentials to our client.
Right now the permission levels on versions is quite limiting - it's either 'Public' (anybody can edit or post to it), 'Private' (only the owner can see and edit it) and 'Protected' (only the owner can edit, but anyone can see). Would it be possible to create a function for 'Protected' versions that would allow you to specify what accounts you would allow to edit/post to it? (i..e User1 and User3 can be given the ability to post to the 'Protected' version, but User 2 cannot). To take this one step further, can you have the same sort of specification for 'Private' versions, but include the ability as to how can see it?
As far as I can tell, this sort of functionality does not yet exist. I'm working way back at 9.2 SP3, but I haven't seen any information like this in the 9.3 documentation or the 10.0 "What's New" info. If such a change could be implemented, it could be quite helpful in fine tuning who can and who cannot see or edit specific versions.