I would definitely ditch the brown marble and go similar to the window sill. It is just beautiful. It looks like Carerra but you can find similar tiles that are from Chinese quarries. Marry it with white paint and add white and grey tones to your accessories. You could accent it with any color as it is a neutral. Brown dates very quickly where is white marble is timeless and classy. Good luck!!

can you inlay it into a metal or timber frame ? then that way it doesn't look odd ? no need to glue? the legs then can be screwed/welded into your frame?

I would inlay it into a frame..ie with a base to hold the marble..then that way you can screw/weld the legs to the base of the frame..

Something like this would look amazing! I'd like to do something similar for my island bench with draws on the kitchen side.