Usually landlords and/or any type if financier is going to require pay stubs as proof of employment. Last 3 months worth or something like that. Have you been able to rent before just using a letter from your employer? I suppose it would depend on the landlord, and how motivated he is to rent his property...but right now it's not a renters market. Tons of folks damaged their credit and foreclosed on homes during the recent recession, so landlords can be pretty picky considering how many people are looking to rent.
It's definitely a buyers market. Way more homes available than there are people that are credit worthy. If you can pay cash for a home there are great deals to be had!