The ignition coil is another possibility. In my experience their bad side surfaces when they get warm. Just another possibility.
Electric fuel pumps tend to bite after the car has been driven 15-20 mins or miles(depending on speed) and will not restart until the system has had a chance to cool off. That can be 30 min to an hour or more, depending on ambient temperature. From what I've read, your situation does not sound quite like this.
Someone in this thread asked about the crank position sensor - CPS. I do not know if it's resistance specs are listed at the following site, but you might check:
http://mb.braingears.com