If we could have found a serial controlled tuner with the right characteristics, we would have used it!

The mk1 tuner is an example of problems with using non-automotive modules in a moving car - bad multipath problems, etc. Car tuners have a lot more circuitry to deal with this sort of thing than the average portable FM tuner.

More tuners will be made, I'm pretty sure - it's just a matter of when. However, when these are all gone, it's very unlikely that any more will get made as it'd be hard to sell an entire sensible-sized batch. That is then the point where it'd start to be sensible to look at rolling your own design.

Hugo