Anybody else into this? An entire desktop computer to model the biggest, most powerful grand in a massive concert hall and I go and simulate a - living room upright.

Not so unusual I believe.

Users can share FXP files here. Perhaps a few more charming/clunky U4 settings wouldn't go amiss?

You can lift the lid on all the models including the uprights now in Standard and Pro.  Not forgetting the universal condition slider you suggested. 

Modartt themselves made a toy piano and a Kalimba in their official Pianoteq instruments, nevermind your relatively massive small home upright!.

I also got the Upright, and to be honest, that one excites me the most right now. I've had tons of fun modeling the old piano you may have had as a kid. It's a small upright, with seemingly high unison detune, short strings, slightly harder than they should be hammers (mostly at light velocities) and a bit of the age slider thrown in. it's a bit tinny, but has that charmingly out of tune/metallic tone. Extra points for putting the mics/head a bit far away and the piano right up against the wall, and you want a small room reverb. This program really makes a good impression of this sort of piano and it's just as fun as playing any of these grands I'll probably never see in real life. It's different than my old digital, which sounded tinny and metallic, but never in a charming way, and never as alive sounding as this software does. I never had a real upright piano as a kid, but when I got to play one it was always sounding like what I've said above.

Anybody else into this? An entire desktop computer to model the biggest, most powerful grand in a massive concert hall and I go and simulate a - living room upright.