I think you're talking about the qualifying ratio, right? It used to be that standard loans would only let you borrow enough so that 28% of your pay went to housing (PITI - principle, interest, taxes, insurance) and 36% for housing plus debt (PITI + car loan etc).
These are not so standard anymore, but with sub-prime loan problems in the US loan rules may have tightened.
A quick check on monstermoving.com gave me one lender who's Nevada loans allow ratios of 45/45 (S&L Home Loans).
If this was the nature of your question, it belongs more in "Housing" than "Taxes".
Good Luck!