I haven't seen anything like this of the sort being used in a level. However, the possibility still remains quite easy to do, in fact. I wasn't really wanting to do this after I started but I managed to complete this graphics pack of mine which contains an assortment of graphics - that are all in black and white!
Behold - the Monochrome GFX Pack v1!
Download the Monochrome GFX Pack v1
I will be adding more graphics to this over time until we get all the graphics in SMBX recolored in monochrome format. Give credit if used.