There is an excellent review in Amazona on the Grind :
Lots of good information here ( yes you can use translate on this ). Really precise detail on all the improvements made to the Plaits core. I thought the small section considering alternatives was interesting - are there any ? While the audio examples here are not as extensive as many Amazona articles, they are illustrative. ( Too much of that Kraftwerk bass riff though. )
The article makes mention of this and says Behringer has announced that new engines can be added with an update, and i guess may be expected at some point. You are right on the mark !