I recently bought a second Arturia Beatstep for cheap and decided to make some small "hacks" and rackmount it to fit my Eurorack modular. It's a very simple modification and I plan to add some more features to it in the near future, like moving the CV and Gate outs on the panel of the Beatstep, powering it up from the main Eurorack bus, and lowering the white plastic chassis as much as possible.
Follow these simple instructions to mount the Beastep into an Eurorack Modular system:
1) remove all screws from the back cover and take it apart (keep the back cover, it would be handy as synth or module panels!).
2) drill some small holes in the four corners. The distance is about 2.5-3 mm. from each sides. I drilled 2.5 mm diameter holes because I had a 2.5 rail, 3mm. is also OK.
3) put some screws on it. I jused some 2 cm. long screws to get to the Eurorack rail. If you have some 2.5 cm. screws they would probbaly work as well.