When it comes to us flight and space simmers we have been pretty much left out in the cold the last decade or so.
Most companies have gone the console or racing sim/game route when it comes to accessories.
Came across this because for over two years I have been looking for an alternative to the now defunct Joylock Clamp system.
https://forums.robertsspaceindustries.com/discussion/151681/joystick-or-hotas-desk-mounting-hardware
http://www.fanatec.com/us-en/shifter-accessories/clubsport-shifter-table-clamp-us.html
29.95 USD, not sure how much they charge for shipping, but looks like it holds some promise.
The L-bracket is 21.95.
http://www.altrider.com/rotopax-l-bracket/pid/398and sold by a different company.
Before I got my current desk, the Ikea Fredde, I used of metal braces and L-shaped brackets to make a mount for my X65 HOTAS system. The brackets worked; but the system was fixed, the corners were sharp and dangerous, and it required drilling into the desk to mount it.
Not sure what the shipping would be for the above clamps and for those in North America/The Americas, I believe these objects ship from Europe or the UK (not sure).
More information and examples of use can be found on the Roberts Space Industries form (link above).