Google, Microsoft, GE, Salesforce.com, etc all have excellent sales and marketing executives who have driven their success and play a key part in relaying customer feedback to the organization. So, yes, you need the rainmaker if you feel you and your partner do not qualify. In my mind the technologist & rainmaker comprise the left & right hands of any company.......you need them both and one only suffers if their counterpart is not supremely talented.

Questions:

What stage is your product? Enterprise or consumer? Are you at $0 Gross Sales or $1+ and building? Are you building TNBT or seek to exit early? Are you bootstrapped, how do you compensate this individual?