On the various manufacturers' websites I see the input wattage, but what do these lamps equate to in Tungsten terms ? For example: Is a 30 watt Z50 Zylight putting out 30 watts at full wick ? Are there equivalents to 300 and 500 watt tunsten floods ?

My best suggestion is to contact the manufacturer directly. There seems to be so much variation with these products that that might be the best route in terms of getting your answers.

As far as a 300+ Watt equivalent, good question. Perhaps the LitePanels 1x1, but that's a huge light.

No idea otherwise.

I've seen a (roughly) 12' x 12" display, which might have been the Litepanel product. The demonstrator suggested it was the equivalent of a 650 watt tungsten lamp. I guess it comes down to measuring lumens at different points.

Perhaps when there are more similar sized products offered someone might publish a piece comparing them. There are a few small head products already.

Aside from the prices - I guess manufacturers are recovering development costs and also maybe pricing for novelty value - LCD seems to be quite user friendly. Their efficiency reduces the tendency to cook a subject at short range.

sorry - that should be 12" x 12"

...and LED. I must proof-read these !