I use the open-source MameWah front-end.

For candidate MameWah backgrounds, I took two screen captures from a YouTube video of someone walking through the New Retro Arcade virtual games room by Digital Cyber Cherries Ltd.

I superimposed a picture of my MAME cabinet onto the screen captures to create two possible backgrounds: background_01.psd, background_01.jpg, and background_02.psd, background_02.jpg.

Currently I'm using background_01 (renamed "main.jpg") with this MameWah layout file.