Hi, I'm WhiteDragon25! While I don't have the technical expertise to actually create a mod, I do have a wealth of ideas and concepts for one. You can see my mod ideas here on my profile blog, where I talk about them in detail.
This old concept art from the sadly-cancelled Tiberium FPS caught my eye one day when I was trying to come up with a GDI Tier 2 vehicle to round out my roster. I was still having trouble conceptualizing the vehicle and its intended role, and this concept art I took note of and shelved it as a possible chassis candidate.
Now, months later, I finally hammered out the vehicle design I have in mind, and I used the Roughrider's chassis as a basis: the vehicle's primary weapon would be an automatic grenade-machinegun mounted on a turret, with a secondary automatic mortar added when the Mortars upgrade is purchased; the vehicle is supposed to be a combined garrison-clearer and light/medium artillery vehicle for all GDI subfactions, a fused-counterpart to the Nod Flame Tank and Beam Cannon.
Funny story about this concept art when I first came across it: the bottom half of the image I mistook as a different Roughrider design, when in actuality I was looking at the rear end of the vehicle from the top half! I felt quite embarrassed when I realized that. ^_^"