Sweden does something similar, they offer unlimited regional rail passes for 1-2 month period during the summer - theirs are quite a bit more expensive than this though. I think closer to 100-150 euro for 2 months if I remember correctly.
I think most federal states in Germany have regional tickets for students for the summer vacations. It's probably going to vary a good bit, but here in BW it's 25~30€ for the ~1.5 months.
