You might find a used TFT monitor like the EIZO L365. It fits well next to a vintage Mac and has two separate input ports for analogue as well as for digital video input. Best of all: it has a brilliant panel with a native resolution of 1024 x 768 pixels, perfect for a lot of Macs. Just get a cheap (passive) VGA to Mac DSub15 adaptor to connect it to the mac video port. (Or cut the original cable and solder on a Mac style DSub15 with appropriate sense pin connections.)