I just stumbled across a 3D engine with really impressive graphics for an open source project
Ignore the DShade, Deadlock and Boxen parts of the video but be sure to watch til the end, according to his other video named "Sponza Party" it shows 50 deferred lights, 100k particles + distortion, glare
Must be that good cause it's written in D
http://h3.gd/code/nucleus/
This guy wrote his Master's thesis about it and it seems to use an interesting new approach.