I have a little bag made by Timbuktu that might be able to attach under your bottles. The attachments are all velcro. Mine is a small and it fits tire levers, patch kit, CO2, and a tube or a micro pump (but not both tube and pump at the same time)

and its stylish...

http://www.timbuk2.com/tb2/retail/ca...87&skusetId=83