Hi Matador,
A wall stand for €69,- sounds like a good deal. The tabel stands that I have seen are around €150,- (pay attention to shipping and import costs).
Other alternatives besides a 2nd-hand original are either a self-built stand, or a 3D printed stand similar to the original.
A 3D printed stand in metal will easily over exceed €150,-. But if you would print one in ABS or PLA and you know someone with a 3D printer, it could be affordable. ABS can after printing be finished with a metal look.
Anyhow, of course you also need a 3D model of the tabel stand. It could be that someone had designed it before, or you need someone to design it.
By the way, I have a 3D printer and I also design 3D models. I could create the BeoLab 3500 table stand if I had a physical example.