Somewhere on this forum (I think in the thread on Certified Lotus' TC restoration -
http://www.lotuseuropa.org/LotusForum/index.php?topic=1704.0) there is a note about other cars that use the same ashtray. I searched around a little but could only find where Certified received his ashtray (
http://www.lotuseuropa.org/LotusForum/index.php?topic=1704.180). It might have been mentioned somewhere else on the forum.
I don't think it will be easy to find but if you know which cars they came from, you'll have a better chance. I was amazed that Certified found his. Of course, that was in 2017 so six years later will likely thin out the possibilities a bit. Certified Lotus is still an active member here so you can PM him for tips on how to search for them and he might be able to help you. IIRC, he didn't find it in the US or UK.
I had an ashtray but I decided to put something else there anyway. It was the '90s but there wasn't much that I could find then, the Interwebs being in its infancy, so I ended up settling on a clock. It was inexpensive from JC Whitney but it actually is a good clock. If I were building my car now, I would look into making a place for a double din head unit. I don't know how much trouble that would be (maybe enough that I would give up on it) and I certainly don't know if that makes any sense with your plans for your car but if it does, you might consider that.
