Starting problem in 2008 Wrangler

I've got a 2008 Wrangler X that I bought brand new. It is a right hand drive that I use on a mail route.Ever since it was new I've had an intermittant starting problem.Every so often,I jump in turn the key,and nothing happens.The dash lights come on but the starter doesn't turn over,no clicks no noise.There is no rhyme or reason as to when this happens.Sometimes it's in the morning,sometimes in the middle of the day sometimes at night.Sometimes I can turn the ignition key and nothing happens for a few beats then the engine turns over and starts.I've had it to the dealership many times.They can't ever recreate the problem in the shop,although they have replaced the battery 3 times.

The last time this incident happened was 3 weeks after I bought a new battery.I normally jump start it when this happens and afterward it will start just fine for months at a time.This last time though,all I did was remove the negative battery cable for a few minutes and reconnected.Started perfectly!And started fine since.But it will happen again.

There seems to be alot of others having the same problem,but Chrysler doesn't seem interested in finding a solution.I can't seem to get my dealership to go any further than replacing the battery.Does anyone out there have an idea of what might be wrong?My warranty is expired (39000miles) and I can't trust our local dealership not to run up a big bill while still not fixing the problem.Any help is appreciated.