According to this presentation Lycean has already built one.
In Germany in 2015
At first I'd thought they were talking about a mini synchrotron (first done by IBM in the early 80's) but their approach seems to be much more efficient at converting input power into X-rays using (relatively) well understood technology (highish power electron currents and ps IR laser pulses) to make X-rays through "Inverse Compton scattering."
Naturally there are a) High hurdles to making this work with a compact syncrotron) b) They say they have solutions for them.
That said we are apparently talking 3 orders of magnitude more power than alternatives, which I'd guess knocks exposure time from hours to seconds. Critical if you want to put this in a production environment.
It looks like someone has finally built a viable high power X-ray laser.
BTW One of things people don't often realize about laser fusion is that all that laser energy is to turn the metal capsule into (in effect) X-ray emitters to cook the deuterium/tritium fuel pellet.
Obviously if you can skip all that malarky and get straight down to just zapping the pellet directly with a lot of X-rays your efficiency goes up quite a lot.
Handy, given the eyewatering some the USG spent on their last laser fusion system.