I'm about to buy a bunch of Lowel lights but before I go ahead and make the purchase I was thinking about lighting with newer, higher lumen LED's and the benefits of it. does anyone have any insight/opinions on this or how I'd go about it (what models, types, etc. are good?) ? Specifically, LED lighting would...

1) run very, very little power. small battery packs could be used to power everything.
2) don't get hot at all.
3) LED's dont burn out or need replacing generally.
4) smaller, lighter, easier to transport.

I'm wondering about what "pure white" (which LED's advertise) means in term of using a camera's white balance. the implication I see is that i could start out with either sunlight, tungsten, flourescent, house lights, etc. and white balance to that, and then introduce LED lights into the scene which are already white, and everything would be consistent. is this correct? if not, how would i correct either the LED's or the other sources to match? also, some lights advertise 50 lumens, does that seem like enough for lighting? of course it wouldn't be anything for shooting on film, but i'm using a panasonic DVXa. has anyone tried this yet?

Don't waste your time or your money. I have been involved with some LED development for the last few years and they just can't equal the quality or output of incandescent.

it as been discussed at large already but as per your assumption:
1) run very, very little power. small battery packs could be used to power everything.
Leds run with very large current, but low voltage. This is tricky because electronics to drive LEDs are tricky to build.
The advantage is you can build "current pump" that can sucks every electron out of a batterey cell independent of the voltage left in the battery.
Out of this, the LEDs are not really giving more light, but allows to use the batteries more efficiently.

2) don't get hot at all.
LEDs are getting very hot, at least for high power models.

3) LED's dont burn out or need replacing generally.
they are giving less light over the time, but generally that is the main advantage over light bulbs.

4) smaller, lighter, easier to transport.
I do not think so , since most of video lamp are very light and compact. since electronics for led + heatsink make them generaly at least heavy and bulky.

one in all, the LED solution is the future, but for instance it is hard to find a ready made solution (some exists but they are VERY expensive)

For those interested in the technical background to the various types of white LED and their possible uses, have a look at this pdf document... http://www.lumileds.com/pdfs/techpaperspres/SPIE2001.PDF