First off, where do you plan on setting up shop? This size looks good for city or large
suburban area, but it is quite big if the only thing you'll be selling is hookah. As for the theme do some research in the local malls and what not. Modern lounges are cool, but a middle eastern theme done well is amazing.
One of my favorite bars in Chicago, they serve Hummus and other little middle eastern snacks but the vibe in there is VERY chill and inviting. Privacy curtains rock, and when you have a waiter enter your own little area you feel like a true guest. The setup is elevated ground flooring as you can see with some large pillows to lie back on. It's really a matter of what market your going after.