Ugh, this is acceptable, I guess, provided the company is willing to pay an hourly wage. I'm currently in the process of looking for a new gig, and there's nothing worse than being sent a coding challenge that should take about '2 hours' (4-5, more like), and then to get a canned rejection from the recruiter stating the code didn't pass muster. This is especially annoying with companies with DEEP pockets - at least do me the courtesy of paying an hourly wage OR have an engineer on the team go over the code and give some feedback.