No. Unfortunately, neither iCab nor Atomic will work. In fact, no browser based on Apple's Mobile WebKit supports editing in a DIV or IFRAME which is what these web based rich text editors do.
Newer versions of rich text editor packages like CKEdit detect the iPad and fall back to using a standard text field. Some community software, like Wikia sites have a preferences option to turn off rich text entry.
Perhaps we'll see support in iOS 5.x