Yes, and also DCIntrospect. They're encouraging, but don't currently compare to what you can do with, say, live-editing css or with a Javascript console.
Not that I've used it, but RubyMotion is making progress on a related front. A live REPL, styling apps with CSS, etc. Maybe we're not far off.
The live REPL is provided by Cycript (a program I wrote that lets you inject into running iOS/Mac applications: it has a blend of Objective-C and JavaScript syntax with runtime tab-completion; it is used by most of the people doing extension development for jailbroken devices as it lets you dig deeply into any running program quite quickly).
Not that I've used it, but RubyMotion is making progress on a related front. A live REPL, styling apps with CSS, etc. Maybe we're not far off.