I need digital artwork for a history website

I'm building a history website and need an image for the banner. I'd like it to be a picture showing people from different eras starting on the left hand side in Roman times, through medieval to Tudor to Regency and ending in the modern era on the right hand side. The banner size is 910 x 360 pixels so the finished image needs to fit those dimensions.

I attach a simple sketch I drew to give you an idea of what I'm thinking of. I'd like it to look sort of hand drawn rather than graphicy/vector art/cartoonish and perhaps even the colouring could be kind of sepia on the left side end and gradually becoming more colourful as it moves to the right.