I do like the idea of this, and can see it being useful.

However, I'd also warn against using it too aggressively. It's actually good to take little breaks throughout the day. If you just cram more & more tasks into a shorter space of time, you'll be less productive, not more.

If you're working in 1/2 hour blocks, take a 5 minute break at the end of each block, or a 10 minute break at the end of an hour. So, a 30 minute block would see 25 minutes work, 5 minutes break.

Just like when you're working out the muscles in your body, rest is as important as work when it comes to achieving the best results. Cram too much in, without taking enough breaks and you might think you're getting more done, but the quality/accuracy of your work will suffer and you'll actually be getting less done.

But don't take my word for it - try this approach for yourself. Call it an experiment, but stick religiously to the breaks (even if you think you don't need them). You can thank me later :)

Nice hunting :)