Summerboard does not yet exist. For 1.1.1, the devs merely patched springboard to allow a feature that I believe was already present--page views. With the new system you flip between pages sidewards (like the Weather app between locations). It really does have a lot of advantages, because it's quicker, less buggy (doesn't crash like summerboard did from time to time), doesn't screw up on it's animations, and the biggest one for me--icons are always in the same location for your thumb to find (speeds things up quite a bit) AND it returns to the same page you were on instead of having to scroll every time to get down to an app.
You can rearrange the icons pretty easily by editing the plist mentioned in the jailbreak readme (using oS X plist editor). rsbt does not yet exist, but it would be trivial to write such an app, so you can expect it soon.