I use a beechwood bench from Ulmia, fortunately I was able to get it from a colleague who had shut up his carpentry business.
Depending on your budget, you could try
the Dictum shop, which is where most craftspersons in Germany go. Be warned though, that's a dangerous website...
On the other direction
Paul Sellers has tutorials on all things woodwork and includes one on how to make a workbench from scratch using builders pine from a timber yard. Mindful that many people assume you already have a workbench he deliberately shows a method where you can start with rough cut pine and work on a trestle in the garden. I think he's since made a tutorial on how to make a trestle without a workbench.