Concerns about possible compliance problems have some major lenders sitting on the sidelines when it comes to one of the newest products in the mortgage market – payment-option adjustable-rate mortgages. A fast-growing product designed to help borrowers cope with skyrocketing home prices, option ARMs allow borrowers to choose among a number of amortization schemes on a monthly basis. The products are being pitched largely to borrowers with good credit histories but irregular income. …