Remember that you can use Magic Lantern on some Canon cameras as well. Magic Lantern is a free software add-on that runs from the SD/CF card and adds a host of new features to Canon EOS cameras that weren't included from the factory by Canon. This includes long exposures, intervalometer, etc.
Check it out at
http://www.magiclantern.fm/
I have been using it on a 600D for about a year without any problems. You dont need laptops, cables and gadgets to do long exposures or timelapse anymore.
Theo