Multiple passes, deferred lighting
Here is a screen shot of the result:
I still dont have properly sorted translucent geometry, but at least its rendered as part of the whole process; i only wanted translucent geometry for things like shop windows and street lamp glass, so hopefully not too many bits of translucent geometry will be visible. I'll fiddle around with the depth g-buffer and the depth of each translucent fragment to see if I cant figure out some way to do additive blending on translucent geometry without depth testing, while still only rendering it when its in front of the previous pass. Most translucent geometry in reality will be clear (not coloured) glass with a dirt texture so the colouration wont be an issue.