If you use the app Extended Controls, you can put a switch-type widget on our home screen that can lock or unlock the autorotate feature. Will lock it in portrait. Also, in settings, you can uncheck the auto-rotate screen under Display settings.
The number of widgets you have on the screen will determine how quickly the screen will re-organize when you change landscape-portrait and back. I have LPP on my X and, with 7 screens, the shift takes a couple seconds. Not a deal breaker for me, but could be if I were in a hurry.