As long as you convince DOSBox to use the Serial port directly (which, annoyingly enough, takes some effort), the SpaceOrb works perfectly with Descent and Descent II. You have to uninstall or disable the Windows controller drivers if you have them installed, and then use the DOS preloader utility that came with the controller. I think it can still be downloaded somewhere.
For modern DirectInput games, of course, the controller drivers for 2K/XP are unbeatable. Add Joy2Mouse with a custom configuration and you can drive both mouse movement and joystick axes with the SpaceOrb, as well as keypresses.

You're in luck-someone's made a gameport-to-USB adapter just for these old digital gameport interface SideWinder sticks! (Coincidentally, the driving force behind that project was Descent, seeing as the 3D Pro was a very popular joystick among Descent players that weren't packing Spacetec controllers.)

Oh wow that's awesome. I used to know KoolBear too. Back when Descent was still popular I made levels for the game. Not many, but I knew the modding community and they knew me as well.