[nbleak21]

I took a welding class when I was in college and my final project was a removable roof rack for my car at the time (97 civic sedan). I welded 4 "feet" on the carrier basket which were lined with foam, and had 4 pieces of flatstock that pivoted from basket down into the area where the door closes at which point they angled in, securely "locking" them in place by shutting the doors. install and tear down took less than 2min, and no modifications required to the vehicle!

I doubt something along those lines would be viable, so I'm on board with the others in a quick release cotter-pin system, or rain-guard hookups if either of those will work.