When does a non-technical startup require a CTO?

I have been interviewing with an e-commerce startup that just raised some VC and is looking to expand their technical team to start building out an architecture which can sustain their future growth.

The business was began by Ivy League grads who are business savvy but know very little about technology. Due to this they have had an interim CTO making all technology decisions for them from the opposite coast. They are eager to hire a CTO and are very uncomfortable making any decisions about platforms and solutions without the opinion of someone who has a track record in e-commerce . . . however their own business model and business philosophy are based on the idea of changing the status quo and building something new and exciting. Therefore every CTO they have brought in has not been a good fit.

My question is this: At what size does your startup need a CTO? For a clothing e-commerce solution with two full time programmers and no other technical staff, is adding a CTO to the mix complicating the political structure? What would be another solution then hiring a full time person to make the non-technical Executives of the company feel more comfortable with the technical decisions?