It would probably help if you included some photos. There are all sorts of Block of the Month patterns & it's hard to give advice without knowing what kind of BOM's you pieced. If they are coordinating colors in traditional blocks, then you could easily just add a 2" strip of sashing between them & make the quilt as large as you like, then add another 2-4" border around the entire thing & bind.
If you have a number of coordinating blocks that are similar, you might look at this example of a JAF setting kit:
http://www.joann.com/search?q=block+of+the+month
(of course, the fabrics in that kit only match the 2015 JAF BOM's, but it might give you an idea)
Here are some other examples of setting kits for prior JAF BOM's:
http://www.ebay.com/itm/JO-ANN-QUILT...item235492ee46
http://www.ebay.com/itm/Jo-Ann-Fabri...item3cfe1138aa
http://www.ebay.com/itm/Joannes-Quil...item25a8f10ff1
You can find many more ideas by googling "block of the month setting kit".
Keep in mind that in addition to quilts, you could also make table runners, pillows, bed runners, and so forth. Good luck & happy quilting!