hate to be the person to tell you this but you can shorten zippers!! you can make a long zipper any length you want...
first close the zipper, you would not want to cut or do anything because the pull would come off and then you wouldnt be able to use it.
measure how long you want the zipper to be and zig-zag over the teeth of the zipper at the measured length, then cut off the extra length. its as easy as that, im surprised that no one else mentioned it.
i use a magnet, and stick it to my machine (of course it only works with metal machines) and use that as a guide - - i have also been known to lay tape on my machine and draw a line on the tape and follow that as a guide (for like 3 inches, considering the lines on your actual machine only go to about an inch)
i 2nd american button machines . . . i have their 2 1/4" machine and i love it, their customer service rocks, and their button supply prices are half the prices of (STUPID) Badge-A-Minit (yes, they are awful)
caution, differnt button suppliers are different sizes, mainly badge-a-minit (becuase they want you to have to buy the supplies from them), just so you know, so if you order parts make sure that they are b-a-m, b/c if not they wont be compatible with your machine (i found this out the hard way, and was so upset about the whole situtation i returned the crappy b-a-m machine and ordered the best machine i've ever used in my life from americanbuttonmachines.com.) FYI
they have those at jo-ann's, i personally dont have one, i sit on my floor and hammer away, but . . . they have directions on how to use it on the back of the packaging, go to your local craft/fabric store and look at a similar product and read the directions.
i bought mine online at americanbuttonmachines.com, a heavy duty machine, but totally worth it. if you want something cheap (and you'll get what you pay for) try badgeaminit.com, they have cheap ones that run about $30. dont know about not buying offline tho . . .
so. . . i was looking over the book and it is seriously close to these instructions (found on craftster, see we're just as good as she is) i would say try out these instructions, and if you feel you want to try something more, buy the book, its not really that expensive.