https://www.spiderwebshade.com/jeep-products/jeep-type/tj/sw1-lj/
I actually got one of these for my TJ. It gives more coverage in the rear and, as
@glwood mentioned, you can fold it behind the front seats to make for a calmer ride up front if it's just for two.
I don't think it would be too difficult to fab one up, especially if you can sew and add the grommets. The material is cheap. I'd make it slightly larger than the typical spidershade, as they do not extend all the way to the roll bars and the sun occasionally comes through right in your EYEBALL!