Well it's done. The Empire has finally gotten its Sub menu and upgrade system.
To allow the player to switch between 4 menus (capital ships, frigates, corvettes and research) we've added 4 new buttons to the GUI, located at the lefthand side of the screen.
Here's a little preview video:
http://www.moddb.com/mods/secret-weapons-of-the-empire/videos/sub-menu-and-upgrade-system-preview

@Locutus: yeah I know, it has to be more exciting

Will that be only GC, or will it be in everything?

Only in GC....but, hey, why do I have to tell you this? I mean you're one of the lucky guys who got the beta version

If it modifies the entire UI, why can't an LAU be applied to the button itself to work on skirmish?

I've had the same idea, but all LUA scripters I've asked said that you can't just lock and unlock units with LUAs.
Another thing is that those buttons show only up in GC mode, not in skirmish, but I guess that depends on how you code them.

I'm personally of the opinion that if you need submenus to fit all your ships, you have too many ships.

It's still some nice innovative coding though.