If you're using normal sized paper (eg between 5 to 30 cm), it's possible to reach a rate of one crane/minute, or even 2 cranes/minute. This works out to 20-30 hours of folding, so it's doable in one weekend. The problem is when boredom sets in...
Remember that It gets faster once you've done a few hundred or so.

I've seen someone do a crane from 3 inch paper in 10 seconds. The trick is to leave out the unnecessary precreasing steps, eg the preliminary base precreases, the reverse fold precreases. These can take up quite a bit of time.
As for history, a search would probably turn up a lot of information on the Sadako story; David Lister's article is one of the most comprehensive ones on this topic. Beyond that however, there seems to be hardly any information about the earlier history of the crane. The Hiden Senbazuru Orikata, supposedly one of the oldest known origami books, deals with multiply connected cranes:
http://www.origami.gr.jp/Model/Senbazuru/index-e.html
Hey, and no shame in loving simple folds - look around some of the other messages in this forum, and you'll find that a lot of folks lean towards simple and elegant folds such as these!
