Taxes-Working out of your home state

I work for an IT consulting firm in NC that requires 100% travel around the US. Most engagements are 3-6mos. This is the fourth company that I have worked with during the last six years; however, it is the first company that requires consultants to report hours worked by state. None of my peers have experienced this situtation. The result is that each consultant will have to file several state tax returns at the end of the year.
Has anyone else encountered this practice? Can you refer meto any tax guidelines or policies?

Thank you