You may be able to contact gibson through their website and see if they offer any. Otherwise I recomend looking at your local guitar store for replacement parts. The one near my house carries things like that, but most are for Fender guitars. If nothing else maybe the local store could somehow order it for you. Idunno, just some suggestions.
-->Jimi Hendrix Wah-->Ibanez DDL-10 Delay 2-->Danelectro Tremolo-->Dod 270 A/b Box-->Danelectro Phaser or Dod Fx 75-C Flanger-->Arion Sch-z Chorus-->Dod Fx 42-B Bass Equalizer