I'm not even sure if there's ever been a Pittsburgh meet. If there has it's probably been over 10 years at this point.
There were many held between 1999 and 2006, with the latter being the first multi-day national meet. The last SWPA Meet was held in December 2010 but it was not focused on Pittsburgh.
The reason there hasn't been a meet in a long time is because we covered a lot in those years. For example, everything on your list except for the 28 upgrade and the 837/885 interchange has been covered during previous meets.
I suppose I could throw a few more ideas on. If any locals have any better ideas feel free to add them.
I can understand wanting to have lunch at the original Primanti Brothers, but parking in the Strip District is scarce on weekdays and pretty much non-existant on weekends. Meets have been held at the Pleasant Hills and North Versailles locations because people could leave their cars there during the tour without having to pay for parking. Out of all of the meets, only one prior to the national meet was held inside the city limits due to the parking situation.
Turnpike 576 makes for a good centerpiece of a meet, which it has been in previous years along with Turnpike 43. Laurel Hill Tunnel is on the Westmoreland County/Somerset County line and is an hour and change from downtown Pittsburgh.