Hi James,
I'm glad that you liked my style...
Here's my method...
Sketchup image with color or sometimes I render it with GI then fotosketcher, no edges to photoshop, 100%
line work from su overlay it with color image 30%
grey layer in ps with texturizer filter, overlay it. 100%
another layer, run it with brushes and eraser, 5% opacity, overlay it 50%
That's it....
allanx