John this is interesting especially given your recent video post to stop thinking like a CIO. The merger of these two thoughts should mean that a background in finance is a great start for a career path to the CEO office even if that means passing through the CIO role. But two other thoughts come to mind.
First, many CIO's and mid-level IT managers neglect developing their business acumen altogether but still carp about not getting a seat at the table. Financial literacy is often missing in IT management career development so by the time you hit the CIO office you still can't read an income statement or explain what <a href="http://blog.thehigheredcio.com/2011/10/30/project-selection-criteria/">net present value</a> has to do with choosing IT projects.
Second, for many organizations IT reports to finance and the CFO I say because of the previous issue of CIO's not be ready to lead financially. So, having a background in finance would strengthen the ability of the CIO's ability to work more closely with the CFO on their terms possibly more as a peer. It would also allow for ascension if the finance background was strong enough.
I think most CIO's overvalue their technical background and underestimate a strong business sense and financial literacy. If there was more self awareness for the balance of these in the CIO office more CIO's would struggle less with being strategic and for transitioning to CEO or other senior executive roles.