I have released a dual window tab browser, Duet.
It features a simple and elegant user interface.
Duet allows you to use two web browser windows simultaneously on iPad’s wide screen.
In portrait mode, the screen is divided into top and bottom windows; and in landscape mode, the windows are located side by side.
Each window can open up to four tabs, so it’s easy to switch between web pages with a single tap.
Please check it out at Duet support page.
App Store Link
Duet Lite (FREE version)