I know it's a seriously long shot but there is a custom rubber parts manufacturing plant about 10 miles from me. They formulate the rubber in house to whatever durometer is required and can embed metal into the shape. The serious drawback is they need a valid CAD drawing; but this was about 15 years ago I talked to them about some tractor pars that were unavailable at the time. I don't know if CAD is still the thing. Regardless, they need a workable program that will allow them to build the forms. They were not capable of making the embedded metal parts but could incorporate them into the part correctly.
It's seriously long shot because they wanted $1,000 for that small round rubber part I wanted to make, that $1,000 did not result in a part though, it just resulted in a prototype. To continue they determined the final cost of creating the individual parts from what the prototypes cost. Minimum part count out the door was determined by size, in this case it was 5,000 units.
I do not know if they are capable of continuous linear extrusion of parts or if they are if a hollow linear part like a panel seal might be possible it might only be possible if it's solid rubber. I just don't know, I haven't been there in 15 years.
