Hi Dom,
Yes, Esther shared the BMP tip with us awhile back, and I've found it useful. I typically like to render at 3200 pixels wide by whatever the height would be for that width. I've not had any problems, but I only render those on HyperVue. I've got 4 Core Duo's at my home which all are used for the render.

I don't know about your renders, but I typically like to use GA with Spectral or Standard atmospheres. AO, GI and Radiosity chew up much more rendertime..perhaps cycles as well. Of course your renders are so stunning I doubt you'd want to change any of your settings.

Also, I got a tip from Jim Coe (I believe) about PhotoZoom Pro 2 which is incredible at ENLARGING existing images. If you don't own this software, you will want it. Please check out the trial as it's unbelievable what it can do.

HTH,
Chipp