Not DIY, not ripstop, but Leo Köhler make pants (trousers) and shorts from what’s commonly called “German Moleskin”. Different from the UK type as it’s shaved on both sides, and some say not actually moleskin, but very robust regardless. Really comfortable on skin too.
Didn’t seem to be a problem to find, first result below.
https://www.moodfabrics.com/bayonne-navy-organic-cotton-ripstop-422264