Having just stitched my sides back up, why not look at it from the stand point of standing a few steps away from the box and not with the face pressed against the outside.
From the stand point of the requirements of two bottles plus a tool kit ( providing it is not a Snap on Tool kit in a bright red box.)
If the frame bidon carrier can take the weight and the size allows, use a 750ml bottle, and then a 500 or 750 ml bottle on the aero bars, a cheap bidon cage, some tie wraps and old inner tube to prevent the paint from getting scratched would suffice or purchase this
http://www.tredz.co.uk/.Profile-Design- ... wwodJ60A2wNow tools, assuming you want tyre levers, CO2 bottles, Allen keys these can be put in a small pouch and kept on your race belt, I have use this method for two middle distance and two IM races, and just tape a couple of inner tubes under the saddle. The aero properties are kept intact, and no bidons firing off from rear mounted cages. Just remember to remove the pouch prior to running.
Extinction is the rule. Survival is the exception.