Bonnie Hunter shared this technique on her Facebook page back on July 6. This might be what you need.
http://www.pinterest.com/pin/41869471510873623/

OMG!! That first one from The Modern Quilt Guild is IT!! How simple and easy could it possibly be! No restrictions on size or proportion, nothing. I'm in heaven!! :D

I have a decades old habit of designing quilts before I ever consider how to actually construct them. That MQG link just moved three designs from the 'dream on' file to the 'reality' file! Set them free, just like that. Thank you so much, yngldy, I'll be indebted to you and the MQG forevermore.