I just ordered a new mercury vapor lamp today. When I saw it, I was throughly impressed by the 60 lumens per watt rating. This 400 watt lamp is 24,000 lumens, which is very good for a mercury vapor this size. Plus, it's a BT-37, not ED-37 like most modern lamps. See here.  

Beautiful lamp shape. These are durable lamps (EYE HF400PD)

The light output/efficacy is to some extend a trade off vs the lifetime. Of course, with good design and process control you may get better trade off...
The rating looks like that lamp was made around European design: Here the 60lm/W was quite common for these high wattages (although it meant a shorter life - mainly because of faster lumen depression; but more frequent changes were justified by the energy savings...)

IMO, the life of this high quality EYE lamp can't be any less than those chinese Sylvania and Philips lamps. If Sylvania had not closed the Manchester plant, I would have bought that.

I eagerly await photos of the actual lamp. It seems EYE lamps aren't very popular; the only one I've seen in person is mine, a SBMV that I got as a birthday present. It also came from 1000Bulbs. I suppose they're not common because most people buy lamps made by the Big Three, not knowing that the EYE lamps are often better quality.

I eagerly await the lamp! It's my Valentine's Day present.