We have no plans of offering an iPhone app for the Jester TLXtra or any of the Jester range - these products do not feature Ethernet capabilities so adding an app would involve a complete redesign of the product.
When you move from Run mode to Program Mode on the Jester TL(and TLXtra), the outputs of your channels and fixtures do not change. Therefore, you can set up scenes and tags as required in Run mode, then jump into Program mode to record the cue. So yes, what you ask for is achievable.
I hope this helps - if you'd like any more information about the TL or TLXtra, don't hesitate to let me know,