Get a Millenium frame! Ok, it's not strictly speaking a scroll frame but it's AWESOME! And beautiful. And it's really easy to tighten your fabric and it's way easier to set up. It goes up to 36" in bars as well.
http://www.needleneeds.co.uk/store/en/n ... frame.html
I want one so bad. This girl had one at this class I went to and OMG! It's soo nice!
Something to keep in mind- you only really need one set of side stretchers with any scroll frame unless you plan on having more than one on the go. Then you can just buy longer bars in order to do wider projects, but still use the same side bars. Saves on the cash and gives you a lot more flexibility. Most places online will let you buy a set of just the rollers without having to buy the side ones.
Whatever you get look for good quality wood. Wood will take a lot more battering than the plastic and is less likely crummy ole when yr boyfriend steps on a corner =( And don't believe it when it says no stitching required(unless it's the Millenium). Your work will always look better if you set it you properly and pull sideways as well as up/down. The millenniums the only one that seems to keep it properly tight without stitching.
Also, I prefer ones that come with a third bar across. That way you can put it in a stand without clipping to your project. These tend to be the larger frames anyway.
Personally, I don't like clips. I bought a clip frame two years ago, and I always just sew things onto it anyway. I don't feel like the clips give adequate, or consistent, tension across the fabric.