Image taken from sbflashlights.com
Spark has a couple of new models out called the SD6 series, one a cool white tint 500 lumen model, and the other a neutral tint 460 lumen model. These are very similar to the well-received ST6 series, except that they have no projecting reflector and are thus a true flood light. These are also powered by a single 18560 battery which is delivered to an XM-L led, just like the ST6 series. A different light output levels are used, but the overall efficiency and highest setting appears unchanged.
Again, this is a full flood light, unlike the ST6 series that have a large hot spot. It will be interesting to see if the flood from an SD6 will exceed that of a ST6. It may in fact have more flood, since with the ST6 efficiency is lost through the diffuser, or if you don't have the reflector in then light is being lost along the deep well of the reflector compartment. Personally, I think the option to have a large hotspot like the ST6 while caving is preferable, however, some cavers may disagree. For those who want full flood, this light will give it to you in all its wonderful, unrestrained glory. It's worth mentioning that this is currently the brightest mass-produced flood headlamp that I am aware of.
The brightest spot headlamp (an HP11) on your helmet.
The brightest flood headlamp (an SD6-500CW) on the same helmet.
What a perfect and enviable combo!! Perfect weight distribution. The ability to vary levels of spot and flood. The complete package, including shipping, batteries and a charger for under $200. Who needs to waste $600 on a Rude Nora or even more on a Scurion? It's nice to have it all in one package, I agree, but I don't know if it's worth paying three times as much for that convenience. And remember, two units instead of one doubles reliability.