Wow thanks, not much to patent and very expensive. By default it's copywrite though.
I am trying to sell it to major retailers, as all my kits. Tough to get a foot in the door. The kit will have an MSRP of $149CDn (much like to Parallax BOEBOT)
There are many gearboxes from Tamiya, the one you've linked to is the Twin gearbox. (won't fit on the Mongoose) it is a nice gearbox and was going to be the one used in the original Mongoose.
Here's a drawing of the Tamiya Double Gearbox (Mongoose) The RED area is plastic that has to be filed away to make room for the opto sensors. **broken link removed**
and the Twin Gearbox (will not fit the Mongoose) **broken link removed**
PS if anyone wants me to post the .skp file for the Twin Geabox just ask. (I won't post the .skp files of my kits sorry)