The ***easy*** way to make a tumbler quilt is to buy an Accuquilt Go! or Studio die cutter. They have two sizes of tumblers and you can cut anywhere from 4 to 10 tumblers at a time. The corners are nipped off, making them very easy to match and sew. The downside to this, of course, is the cost of the die cutting system.
Here is a link to a Yahoo! email list about the die cutting system:
http://groups.yahoo.com/group/accucutquilters/
The photo section has several tumbler quilts.
If you are interested in that system, be sure to read the old messages on the group to find out how to get the die cutter for considerably less than suggested retail. (I got mine at
http://www.shoppersrule.com when they had a free shipping offer.)