I’m not sure if the “sliding windows” feature is the same as Andy mode, so I may be talking about something else here but…
There’s this custom-css hack(?) that I’m sure is what Cybertron uses if you haven’t seen it already: Andy Matuschak mode - V2.7 (updated for 0.7+ new panes)
So if you want to have this functionality in a light mode theme or with Obsdn-Dark-Rmx, you can.
As for making it a plugin, the guy that made the CSS said this: