The old Irish descriptions of leprechauns says that they wear red, not green, specifically to stand out from social faeries who live in big groups and wear green. Their clothes is decorated with gold, and their shoes are of high quality. Their dress changes from area to area
Only later did they get a pot of gold, a habit that seem to have come from Scandinavia where everything from dragons to trolls to elves to freaking magic chickens guard gold. Back in the day, if you caught a leprechaun he gave you three wishes for his freedom.
If you'd like to see my version of the more well known modern leprechaun, he's over at my DA page http://humon.deviantart.com/art/Modern-Leprechaun-441314072