Cost of clinker brick veneer facade?

Well, there are already enough examples of new buildings with brick slips. There must be a (financial) reason for that,

Yes, brick slips are glued, solid bricks are laid. For solid bricks, masons are recommended (at least experienced journeymen), with brick slips you can "safely" also leave semi-skilled workers on it. That is indeed a "financial reason," although more for the wages; the lower material price is more like a cherry on top.

We build with a traditional double-shell construction and another reason for facing bricks: the walls do not become ridiculously thick. We have a total of iirc 47 cm thick exterior walls! That is much thinner with facing bricks.

We build traditionally with a double shell and another reason for brick slips: the walls do not become ridiculously thick. We have a total of iirc 47 cm thick exterior walls! With brick slips, it can be done significantly thinner.

Why do you then build double-shell? How expensive is your facade in comparison?

We build traditionally double-layered and another reason for facing bricks: the walls do not become ridiculously thick.

Traditionally double-layered there is no option for facing bricks, since facing bricks cannot be built in masonry but only glued on. The difference is made by the material "behind" the clinker layer: if it is a stone or a formwork stone or foam insulation, it can be glued onto. Then facing bricks are possible and solid clinker bricks unnecessary; if, on the other hand, it is fiber material insulation, then it is unsuitable for bonding and facing bricks are ruled out because the clinker bricks must be built as an independent shell, which only works with full-thickness clinker bricks (= one head).

Classically in a double-shell structure, there is no option for thin bricks, since thin bricks cannot be built in masonry but only glued on.

Of course there is, and it's not a bad idea at all. A house two streets over stands like this: KS, insulation, air, KS. On top, whatever you want, here plaster with thin bricks as an accent.

Why are you building with a double wall then? How expensive is your facade in comparison?

I can't say what the facade costs compared to others. In this area, it is common practice to build even plastered houses with a double wall. I accepted it like that; it was not the main criterion in choosing the supplier.