I have a Rigol DHO4204 scope, and it would be lovely if it did not occupy space on my desk.  Luckily, I also have a 3D printer!  On the back, it has slots for mounting a battery that Rigol could never be bothered to sell, but in a post-surgical haze, I grabbed a calipers and measured the slots and modeled up four “ears” that insert into each corner, and a base plate that holds them into position.  The idea is that the holes in the base plate have a little bit of tolerance, so you can preload the “ears” into place with your finger, then tighten the three screws that hold them in place, one at a time, and they'll stay put (and be coplanar underneath).

To build it, print one of each, and insert the heat stakes into each hole on the ‘ears’, and then four heat stakes into either the 75x75mm mounts or the 100x100mm mounts.  Probably you'll want to chase the holes with an xacto knife after you insert the heat stakes, so you can actually get M4 screws all the way through them.  I have no idea why I keep designing with heat stakes.  They are terrible and I should just do captive nuts.

I printed this out of PETG.  I recommend that you do too, but if you own one of these printers and one of these scopes, presumably you know what you're doing.  It is held together with heat-stake thread inserts, so hopefully it's not going anywhere.  But of course if you make this, you do so entirely at your own risk of dropping your $3,500 scope on its face.

Onshape model here.

Parts you'll need:

• 16x M4 x 6mm heat-stake thread inserts (I use these: https://www.amazon.com/dp/B0B46YBNV4 ... but probably nearly anything will do)
• 12x M4 or M5 washers
• 12x M4 x 20mm bolts
• A VESA mount kit of your choice (M4 100x100 or 75x75mm)