I know we talked about this on another topic, but I really want to make this. A TF2 calculator, which would allow you to build all of the things in TF2. The dispenser would slowly recharge your health, and the turret, when whacked with a wrench (maybe a modified key mod), would repair/upgrade. Once at 200, the turret would upgrade, just like in TF2! Also, the teleporters could use a sort of portal gun type thing.
I can build models for this.