I think you are absolutely right - for most people they work better under a deadline, I think allot of it has to do with focus. With a deadline you are forced to have laser focus.
I've worked on projects with a deadline of 2-months, and it takes me 2-months. I've worked on projects with a deadline of 2-days, and it takes me 2-days - almost same amount of work.
With product development, I like to really nail the outline - if its an ebook, then I like to get my topic nailed and the outline of questions leading to the ultimate conclusion. I find once I get everything outlined in terms of questions - I can work a little less crazily.
Same goes with other forms of products - teleseminars, its the questions, a video, its the broad outline and questions I will address.
Cheers...
Jeff