I've just released my XInput interface for Delphi. Supports game pads only (limitation of the library). You can have the full complement of 4 pads connected, provides both eventing and polling style of use (or of course a combination of both). It's tested for Win32 and Win64 compilation using XInput1_3.dll. I've been unable to test using XInput1_4.dll as I don't have access to a Windows 8 platform. The only other thing that I've not been able to test is the battery monitoring capabilities for wireless controllers as I don't have one.
If you find issues etc. please report them through GitHub's issue tracker.
My library is available at:- http://smwl.uk/aoddl