I know right where you're at. Skip the guy in Brookfield and go to that Fleet Farm or Farm & Fleet or whatever the heck they call it - the one on 18 behind that PDQ. They've got 'em. I bought mine there. Home Depot should have them too, but they're a tad more expensive. Otherwise, you can go down to Hwy 100 and between Northern Tool and HOBO there's a Graingers (electrical supply house). (That's right off the freeway on Hwy 100)
You won't find wire easily available around here in 18-22 gauge except for at Radio Shack. Grainger SHOULD have some available, but they seem to sell out of it pretty quickly. You'd think they stock more, but they do a lot more business in mail-order.
If you still want, here's the two distributors for our area and I haven't dealt with them, so I don't know which to tell you (although ponyboy has better prices on buttons/joys than Happs). From the Happs book:
Outside Sales Representative
Eric Skowlund
Tel: 800-511-1796 Ext 470
Office: 262-677-9125
Cell: 847-867-0628
E-mail: eric.skowlund@happcontrols.com
Inside Sales Representative
Dan Trivits
Tel: 800-511-1796 Ext 103
E-mail: dan.trivits@happcontrols.com