Technical advice requested here.

Yesterday was a pretty hot day here in North Texas. I drove from work to pick up my son, waited at his school for 20 minutes with the engine and AC running. Once he got out of school, I dropped him off at his moms house and shut off the car. When I returned, I turned the key and the starter doesn't engage, click, make any noise what so ever. The radio comes on, the vent fan blows and the power windows work fine. I wait 20 minutes, use a set of good jumper cables on the battery and she fires right off. I drive a few blocks to my house, and put the battery on a charger. Well the battery shows fully charged. This has happened several times.

Chances are its the starter solenoid.  If this happens after extended use of the car, allowing it to get really hot(not actually overheating the engine but under hood temperatures for extended time such as idling for long time, long road trip etc.... ) but doesn't happen for a short trip, say 5-10 minute drive to the store for a cola and snickers....   then chances are its the solenoid.  However, I have had the neutral/safety switch under the console(an automatic transmission) actually go bad on me when it got really hot.... but I would focus on the starter solenoid first.

+1 on the solenoid. Check the connections on the solenoid first, but chances are it's time for a new one.

Okay guys, thank you very much.

Any recommendations as to which starter assembly I can go with that isn't as susceptible to heat failure?

It's not the starter, it's the starter solenoid mounted on the starter.

You can get heat shields of varying types to help prevent that heat problem, but with stock exhaust it shouldn't really be necessary.

High torque starter will take the heat. It is smaller and lighter than the original.