1 main monitors with 2 sidekick monitors?

Hello........ Right with the pleasantries out of the way I must ask a question. Before you comment that I should go to a proper forum and Address this, I wish to say that I do not have an account with any of these forums and I do not wish to create one.

The question !!!!
I understand that you can have 3 + monitors for gaming but they are usually set up with 3 monitors all being the same size. However I wondering if I can have One large monitor and 2 smaller monitors on the side in a vertical position ? This is to extend the desktop, the main aim for this is for gaming and nothing else. Now I have heard that you can go onto the graphics control panel, stretch onto all 3 monitors and correct the 2 vertical monitors ?
Would there be any issues ?
Would games have issues, if so would putting the game in windowed mode and stretching it work. ?
If the vertical monitors can behave accordingly at all ?

Why I want to do this ?
Less desk space used up
Cheaper
Lower power

Monitor examples would be: 27inch 1920x1080 resolution with the other 2 with 1600 x 900 resolution ?

In theory would the resolutions mount to: 3720 x 1080 resolution ?
Additional

Thx for the answer but I already know this, can you please read the question again. I have seen it done before.