"I had my father's colleague's son build a prototype for us. It does almost everything the final product needs to do. It took a couple of months and only cost us $4000. But he (the son) is now going out on tour with his band, and we need someone to get us to launch."
This is almost inevitably a set-up for disappointment for all parties. Non-technical founders have no idea what software development costs and how long it takes. They will be shocked at reality and blame it on you, the tech co-founder.
Potential tech co-founders will waste a lot of breath explaining things to the non-tech co-founders that they (the non-techs) will struggle to understand.
Eventually, everyone will be mad at everyone else.
Problem is, much of this also applies to hiring free-lancers. They are going to cost far more than the non-tech founder predicts. The only difference is that the free-lancer will get paid for (some of) his/her work.
Though I'm no huge fan of the VC/start-up model, it's no wonder that it evolved to its current state, where potential ventures are judged largely on their teams' proven ability to deliver.
Wrote a blog post on 5 creative ways to find a technical co-founder - http://bit.ly/rQdvpK