Thanks Saveaux, but I have not found a similar product that works with seat all the way back and reclined and does not requires screwing stuff into the seat. For a moment I though the very nice solution Riven02 is offering would be a good solution for my situation, but unfortunately it is not. The creator of the item confirmed this to me.
Now my hope is that someone has a set of Kappasphere belt-X-tenders laying around that they want to sell just as the ones presented in the first message of this thread.
@RedOne07 At 6'2.5" (189cm) I have to have the seat as far back as it will go. My wife's 5'2" or 157cm and anytime she drives the car she moves the seat forward. When I get in I slide the seat all the way back which usually results in me pinning the seatbelt behind the seat.
I scrolled back to the beginning of this post to see what you were referring to. I may try to make one of these myself as it looks pretty easy, I'll keep you posted!