What is the main cause of the 15min removal time? Removal of the nuts? If that's the case, knob nuts might help speed that process.
Something like this...
http://knobsource.thomasnet.com/category/knobs
Great use of resources, If I find cheap sidecases, i'll definitely need to pick your brain for more info.
Edit: Has the weight or size affected the bikes stability or made it more or less difficult lane splitting?