Any ECU codes? You mentioned none. Check them anyway, regardless of whether the "check engine" light is on.
When it fails to start as you describe, that's your opportunity to identify the problem. While you're along the side of the road have you...
- checked fuel pressure
- checked for spark
- made note of ambient conditions (high / low temps, high humidity, rain, etc.)
- noted any unusual dashboard gauge readings
- used a diagnostic tool, e.g., like DIACOM et al., to see what the ECU has to tell you during the time the engine fails to start
Does it misbehave in any other way at any other time...
- long crank before starting when cold, when hot,...
- failure to start under other conditions than already mentioned
- erratic engine behavior
Is the vehicle history a factor, e.g., comment on...
- rust or corrosion due to sea spray / winter road salt
- major body repairs (can lead to grounding problems)
- major power train repairs (trans swap, engine swap,...)
Sounds like you've replaced plenty of parts. But installing parts doesn't guarantee anything; for example, intermittent low fuel pressure can be due to a poor fuel pump ground and not simply the pump.