Just a little something I whipped up tonight because I was bored and tinkering with some of the GT stuff.  It's Nod Challenge 1 and GDI Challenge 2 with the player as GloboTech with appropriate sidebar, units, decorations, text, etc.  

It'll overwrite the regular TI files and maps, so either make backups or just have the client fix the files when you're done goofing off.  The levels are under the "GloboTech Challenge" header in the campaign selector.