Dan,
It is not illlegal to refinance your homestead (primary residence) using an adjustable rate mortgage. However, the scheduled installment amounts of a variable rate equity loan must be:
(A) substantially equal between each interest rate adjustment;
(B) sufficient to cover at least the amount of interest scheduled to accrue
between each payment date and a portion of the principal.
There are no stipulations under Article XVI, Section 50(a)(6) of the Texas Constitution that it must be a 5/1, 7/1 or 10/1 ARM. The problem is trying to find a lender that will do an ARM on a Texas cash out. Without getting into a lot of the reasons why, suffice it to say that until there is liquidity in the secondary market, you will probably need to locate a portfolio lender to do a Texas Equity loan (cash out) using a ARM.
I hope this helps and if you need further assistance, please don't hesitate to contact me.
Lea Shaw