So, one day, out of the blue, I could not open the little hatch to get gas into my 2003 Honda Civic. Going online, I found this is a fairly common problem wherein part of the cable just rusts out so that the trunk will open (a pull) but the fuel door will not (a push). I also found some guy in Canada who sells a $20 bit of plastic that snaps over the existing cable and makes it work again without ripping out half your car. Instead you have to rip up only the trim in the driver side door bottom—which is tough enough and I don't want to do that again. Seems to work, I'll edit this post if it fails anytime soon.
Anyway, this seems like exactly the sort of thing that could be a plan you download and make yourself in 5 minutes on a 3D printer. It would certainly save on the first class mail from Canada.