I think you can filter out longest and nearly vertical lines, after using hough transform. Check out this link.
SimpleCV is just a shortcut library including OpenCV functions, you dont need to use it. I dont think you will encounter problems implementing the algorithm after getting the idea.
Edit: Ok, I thought more about your problem. Setting clusters to zero as a preprocessing step is not bad actually. What about increasing the window size step by step? I mean after obtaining second image, apply another cluster filter with 2*window size, same threshold. I think you can go on like this, as the wall edges are hard to be cancelled out.
Another way, use a rectangular window (width >= 5*height) for cluster filtering as you need vertical edges.
Another way, play with erosion and dilation and filter out blobs having large area.
Another way, check out the top part of the image, there is only the wall edges and the chandelier. You can search horizontally for a white pattern, then follow its neighbours to specify the length of connected points. Then filter out longer ones.