Here's a more 'classic' light angle, and a few inevitable composition tweaks. I may start saving out as EXR and finally put my dust covered copy of Nuke to use.
Hannes: Thanks! I started off with very low OC and Bounce values and these are the highest I've gone to date. I was using a 2nd sun as a very low value fill, but Oshayn recommended dropping that approach, so I'm still groping toward some reasonable understanding of the GI settings. I'll give the Cubic B-spline another try and post up the render;, my past experience with every other filter (other than catmul-rom) was that the images were 'smudged' to death by the anti-aliasing, maybe there are other tweaks to enhance the result?
Bobbystahr: Software prices from some of these guys assume all users are Studio types with purchase orders by the boatload, makes it tough on the individual artist. Thanks for the comments!
Well, here's another render: