Pre-wired lighting harnesses for driving lights are inexpensive to buy, they're all over sites like eBay and Amazon.com.
Though for LED headlights like we're talking about above, you don't need to add a wiring harness. They are plug and play, they plug into the OE wiring harness with no modifications needed anywyere. And because LED headlights draw so much less power than the OE headlights did, no relay is needed either.
For driving lights, yes there are...I suppose you could adapt one for use with the H4 conversion. I looked into it, but in the end it was better to build my own. Sorry to pull the thread off topic, just wanted to add content as someone was expressing concern over ice and snow obscuring LED headlights due to their lower current draw (thus lower heat output)