Well, your sunbeams look pretty awesome to me  and I've never tried myself... but I remember admiring a contest winner at Corel (Paint Shop I think, not Painter) in the past year.  I snooped around and couldn't find the web page - but I do remember that he drew each beam on a separate layer and added different brightness, drop shadows, blurs and effects to each layer individually.  Such an image must have several dozen layers! 

I don't think I have the patience, but once you do all the work on the first image you can likely reuse on other photos in some way?