I have the Sidewinder Gamepad and Sidewinder 3D Pro Joystick, both gameport versions, plugged into a Soundblaster Live 5.1 card of my WinXP Pro machine, and each works fine with no special drivers (I use the Sidewinder Autodetect). The 3D Pro works even when daisychaned to the Gamepad (so long as I press the button that disables the gamepad for the joystick to work, and at least make sure the Joystick is detected in the Game Controller properties in Control Panel). Just strange that the old 3D Pro gameport version works like a wonder in WinXP and Win2k, but I can't get it to use the Sidewinder driver in Win98/WinME (there I have to resort to the CH Flightstick Pro driver, because the Sidewinder 3D Pro driver only responds with the "Not Connected" message).
Dacs: The Sidewinder Gamepad gameport version has a gameport socket between the triggers where you connect another gameport device to it for daisychaining, though it seems only Sidewinder gameport devices (specifically the Gamepad and the 3D Pro) will work in this setup (if a 3D Pro is part of the chain, it should be the last controller on the chain). The USB versions cannot be daisychained (because there's no USB port on the controller), instead you use a USB hub to have multiple game controllers connected (though many game controller manufacturers discourage this with warnings of instability).