How to make a small DIY bain marie?
Can you repurpose a stovetop coffee pot/percolator?  I prefer the glass ones (do an image search for 'coffee percolator glass', so you can keep an eye on progress throughout.  If you were to replace the drip container at the top (that usually holds the coffee) with a small stainless steel bowl (your standard IKEA type mixing bowl), the rim will be held stable by the coffee pot. 

Plus it already has a handle built in so you don't burn yourself in search of the perfect chocolate ganache!  

ps: I'm in Germany too - I saw some at Tchibo last week.