I have a problem with the concept of expending time and money to create a slow serial display.
What we need is an ethernet enabled version.

So your solution is to spend way more time and certainly more money to build an ethernet device that drives a regular parallel VFD? If you just want faster the 7000-s are 115kbps (28 raw fps), or there's serial->parallel chips that could drive a parallel VFD at 230k (56 raw fps) without requiring an IP stack.

Personally I'm always driving when I'm in my car (and have at most one passenger), so the speed over a few fps is almost irrelevant, whilst the other 3*128*32px on my 256x64 3900-series can be used to show other stuff (like GPS or OBD-II someday) with a simple programming interface. I spent far more time figuring out and building the hardware to make that joystick work than I did putting together functional serial rendering software (though I'm also a software person that knows just enough hardware to be dangerous).