I'm Neilfensteins little bro, I've been trying to learn objective C as well by building a simplefit app, and hopefully we'll be working together on it as it advances.
I've begun implementing pretty much what he described above. Some screenshots below.
Day 1 simply divides the 20 minutes by the number of reps entered. Pop-up to show reps completed
Day 2 allows you to enter your rest time in minutes, the timer counts up only when working out and begins the rest counter when the rep complete button is pressed.
Pop-up shows each rep time and total time.
Day 3 isn't complete yet, but will be a simple timer with a pop-up suggesting levelling up or down depending on time taken.
As mentioned this is all pretty new to both of us so will be aiming for the basic functionality mentioned before, then working towards it being a bit more involved later.
Current ideas are:
Access to the server to log workouts from the phone,
Ability to display the log graphs on the phone,
Settings that allow awareness of current level with the ability to view the workout required for that day,
auto levelling up or down dependant on days 3 time,
Auto levelling for rest week.
Any suggestions are welcome but as Neilfenstein said don't hold your breath. We would probably try and release the basic app then upgrade over time.