The bottom door pieces of the surrounds on both sides of my car were trashed even though the rest of the rubber was okay. I have complete sets for each side, but chose to replace just the bottoms until it is time for paint etc. Looked for just that piece and searched the forum for a solution. Couple of dedicated rubber resources didn't really replicate the profile and were still quite expensive. Finally found a non-identical, but practical replacement on, of all places, Amazon. Trim-Lok is the brand and I believe it was the 1/4 channel with the 3/4 round bead. You might decide on another profile once you find the selection. - Believe there is a one inch as well that would work too.
Worked fine aside from having to tape the bead down with painters tape to allow the closed door to form-fit the round profile to more closely replicate the original over time.
About $40 or $50 bucks if memory serves for more than enough for both doors.
Hope this helps if this is what you were thinking of.
You can see in the first photo that bottom piece is torn & missing in places. The second shows decent original piece butted up against replacement and you can see how the original flattens at bottom versus the round bead profile of the new item. That's why you would tape down to replicate. The third shows the profile prior to fitting on metal trim piece. Photos aren't great, but hopefully tell the story.