TGB In-Game Mission Loader

Have finished a project for a client and am short on time so thought I'd ask before I get started on doing this myself.

I was wondering if anyone has any code for a system like the Starter.FPS has where it gives you a windowed dialog and you can select which mission you'd like to load but for TGB. Should be simple enough so thought someone might have already done something similar and I wouldn't have to spend the couple hours bring it over from TGE.