I've got this song and the chords are:

verse: Gm, A, Dm, Dm
chorus: Dm, A#, C, Dm

I'm trying to give this song a "disco" type of feel (yeah I know, disco's out, but this song is really neat). The percussion, rhythm guitar, and bass already do a great job of doing so. But I'm trying to create a lead guitar rift that has a disco type of feel. Any advice on what scales, patterns, and other techniques I could use? Thanks for your help.

Try a muted - plucked part ala Cheryl Lynns' "To Be Real" or Steely Dan "Peg" . Minor Pentatonic at the 10th fret or D natural minor (aeolian). Pick a 3 or 4 note pattern that's repetitive , it should work over all the chords. When you go to that A major you may want to play a C# note.

Plus, what disco riff would be complete without a wah?!