Personally I have a 29" arcade monitor mounted in a hand-made wood box. The advantage of this is that it is an auto tri-sync and takes both RGBS and RGBHV input. Basically anything that outputs RGB from 15khz 240p to 31khz 480p works. Everything from my MSX to my Dreamcast looks beautiful on this thing, and the size is just right. Also being a proper auto sync it works with my more exotic PCs (Sharp X68000, Fujitsu FM Towns) too. I can also use with PS2/Xbox/GC/Wii 480p using a Component->RGB transcoder.

I believe SONY made some incredible RGB monitors that were used by broadcasting stations and whatnot but I don't have any model numbers off hand.

I'm looking for a cheaper, more available, but still good alternatives - like more common Sony Trinitron TVs (14", 21", 29").

About Sony PVM... I see there are a few 14 and 20" on sale "locally" - more than 100km drive. But prices are from 200 to 500€ - way too much for my taste or needs. Sony TV's are from free to around 20€. Much more price friendly and it's still Trinitron.

Some 28" Philips with L04E chassis is going to be hard to beat, the tube is excellent and it is one of the last fully analog video path chassises they made, later ones use digital processing and are crappy in a number of ways. It also does wonders with composhit/s-video input but is sometimes not super fond of NTSC input (RGB is fine in both 50 and 60Hz).