Single Status Update
I've been working on a new Eternity feature: attached surfaces with linked portals. Normally when you move a sector linked portal's surface, the solid will move, while the portal plane will stay. But with an ExtraData/UDMF flag, the portal itself will move (together with the sector height). This makes setups such as variable height edge portals possible, for such effects as vertically moving objects.
You may want to use the attached surface feature to achieve anything meaningful in combination with attached portals.