I used to use 2 x 28" iMacs connected together to make 1 big desktop. It worked well but it threw off alot of heat.
About a year and a half ago I replaced them with a Mac mini, and a Dell UD4919DW 49" Curved Ultra-Wide Monitor
https://www.dell.com/en-us/work/shop...or-accessories
I love it. I can run it as a single 5120 x 1440 Ultra-wide monitor, or a 2 "Virtual" monitors at 2560x1440 each. The second mode is useful for screen-sharing with programs like Skype.
The monitor looks great, has the usual extra USB ports, and runs cool.
My Mac mini will support additional monitors too but so far I haven't had the need to connect an additional monitor. If I do though, I might buy a second monitor like mine and stack it. It would look cool but it would be overkill for me.