Further to my last....if you are too far from the sea then how about:-
Go to a shop (Borders Books perhaps) that have a good selection of magazines.
Look at the Kit and Custom car mags. Lots of instrument photos in them.
Look at the better yachting and gin-palace mags...pics of radars, echo sounders etc.
Again, scan and print to your size. I actually used pics of my stereo set up as part of the layout, looks suitable. I'll put some pics on here and see if you can use any of them. BY.