Yes, this concept would be idea but is ultimately too difficult to produce. FOr instance, if you set your pace for 1:30/hundred and are going too slow, the workout would continue while you are still on the previous interval. So yes, hypothetically, I guess you could skip ahead if you do lag behind and want the opporunity to catch your breath and jump back in. Maybe the solution to this is to have the option for the workout to be broken down into every interval as its own song or one giant song wherein you can fast forward if necessary…a good point. At the same time though, if you are going too fast for your programmed interval, on each interval, it would be nice to have the ability to start the next part of the set ahead of schedule. if it was made as one giant song, and you were going faster than you thought you would be, you’d have to keep fast forwarding on every part of the set, or take more rest on each interval than you would like to for an effective workout.
Swimman can waterproof an iPod shuffle from the inside so their is no bulky case for a little over $100 and he guarantees his work 100%. you can also defer to otterbox or finis swimp3 if you need an entirely new iPod but i definitely recommend Swimman as the best.