In principle, I welcome editors who create or expand an article for payment (inasmuch as their editing complies with the project's guidelines). In practice, however, it would be exceedingly rare for that type of editing to not be problematic to some degree; the nature of the business world is such that paid editing would almost certainly not adhere to Wikipedia's NPOV policies. Consider this: if a client commissions a Wikipedia article's creation, would the client be satisfied with an article that did not reflect a stance that was at least a smidgen flattering? I wouldn't imagine so. On that basis, I think a blanket discouragement from editing for payment to be the most sensible approach to the issue.
AGK