Mark said that Canton had the ability and was willing to build any of the older models for him. I'm guessing that Canton doesn't want people Googling the latest models and seeing A4L's pricing, so they are not going to give him great prices on the latest ones ... but that is just a guess!
I am sketchy on the Canton lineup/evolution, but yes, Reference-K is on top, then Vento, then Chrono SL, then Chrono ...
Actually, Canton is still selling the A 45, but only in Cherry and I doubt it would show on the US website since Canton probably does not want to get into the export direct to customer business!
www.canton.de