I don't think technicals will ever go away. Whenever the need for having a weapon system now out weights the need for armor, reliability and standardization someone with a hacksaw and welder will appear and make it happen.

Motor/tube artillery seems like the natural first place to see this. The lack of armor isn't a big detractor, an infantry motor team is already in armored, and a simple bubble level to assist with aiming will probably make it accurate enough for use. And honestly the Grad isn't much more than a glorified heavy truck with rockets strapped to it anyways.