That rendering looks great. I had a client want the same style for their project. I rendered it in Artlantis and did a sketch rendering in AC. I did as you, in that I layered the images. I put the colored image on bottom and the sketched image on top. I ran the water color filter in PS on the colored image
then used the texture filter on the colored image to make it look like it was on canvas. I then used the eraser @ 50% trans to erase the sketch rendering
till I got the effect I wanted.
Robert Fuchs
Miller Bosksus Lack Architects, P.A.
2x2.26GHz Quad-Core Intel Xeon w/10 GB RAM
Mac OSX 10.6.4, AC 14 (3004 USA Full)