The web site address ends in ".cz", which is another indication that it is Czech. I can't read a word of it, but recognize the T@B name in the text, which I assume means that this is not just like a T@B, but is one.
I asked T@B (really Dutchmen) here (via e-mail) about the possiblity of a larger unit than the current one, since a T@B dealer said it was being developed. They said explicitly that there was no plan for a larger unit, and their web site
now includes that in the FAQ
. I suppose that the tandem T@B might use a different series of frame (the frame is a component system from Al-Ko, not made by T@B ).