yes just put another layout under the tab layout and populate whatever your gui builds into that layout instead of a window. Or if they have finished making it into a panel then just make a panel layout and parent the panel there.
PS i think open pipeline is a bit misleading name as its not a pipeline system its more of a request / asset /project manager as it is now. Pipeline in my case is the magic that happens to things before and after they leave maya and end up the finished project
When they started they had no clear direction and started doing the worng thing. I mean makinga visual diff would be nice but seriously a versioning system with a pretty basic content manage. Since theres no sane way to diff theres no sane way to pull a merge since theres no merge your linearizing the flow of tools. I get better tools than this using git/mercurial for free.