FreeCheck is a free check-printing utility, currently only for US and possibly Canadian checks. You can use it to print your own checks on blank check stock, available from office supply stores and various places around the web. It generates a PostScript file which can be saved to disk, printed, or converted to PDF using GhostScript.
SamBru (Samsung Backup and Restore Utility) is a Perl script that talks to a Samsung SCH-6100 or SCH-8500 cellular phone. You can use it to back up and restore the phone book. It can save the data in either raw/native format or as vCard data so GnomeCard can be used to view and edit the data.
Re: Integrating into GNUCash
I have been in touch with the GnuCash people... they seem mildly interested. I need to get the fill-out portion of FreeCheck done (amount, payee, etc) and then perhaps they can use it. They're currently using Gnome-Print to fill out pre-printed checks, I believe.
North American Checks
Sorry, that's true, it's only for American (and Canadian) checks. If you'd like to extend it to print checks for your country, I'll accept patches. :-)