If this is an outdoor scene lit only by the sun you should try the Progressive Path Tracing setting. See if that speeds things up.
It also looks like a healthy amount of geometry with the modelled roof tiles and trees. That is probably contributing to the speed.
There are a lot of fantastic images here. It's making me want to keep trying. So I did another one with Sketchup and Kerkythea. Again, there's some post-production done - cropping, levels, a little bit of glow.
I find that I'm having a little trouble modeling the tops of the glasses right. They look too wide. Does anyone have any advice on that front?
So here's my try - sketchup and kerkythea.
A little bit of level adjusting and cropping done post-pro.
Still grainy.
