You could try LEDs, hell you could power them off batteries at the base of the boom pole (weight is better there) but I don't know if you could get enough LEDs into the lantern to get enough output. They tend to have a lot of green and then you need minus green gels, hard to do inside the china ball.

This is the old china ball on the end of a stick trick. Works well with a Tungsten balance pratical bulb, if you can still get them. ECT or something similar. In Europe for daylight balance we used to use incandescent bulbs that had a special blue coating, that made them ca. 5000 deg. Kelvin... good enough. Not very strong, but we'd pack 3 bulbs into a big lantern in a pinch.

Go to IKEA or other source with cheap paper and wood covered china balls. Buy more than one (they rip easily). Buy a retractable painter's pole or use sound operator's boom pole if you have one already. Get an inline dimmer (again IKEA has some cheap, but the fuse is soldered inside, so if it blows you need a back up).

At a hardware store get some zip cord and a porcelain light socket. Rig up the socket dangling 6-10" off the end of the boom pole. Wire up the dimmer to be at the other end so you can easily make is brighter or darker (color temp WILL change). The china ball will grip the directly on the zip cord or use some gaffer tape to attach it. Ex: http://arabellelittle.files.wordpress.com/2011/04/imag0388.jpg

With the porcelin socket you can use as bright an incandescent bulb as you can before the paper of the chinaball lights on fire (that's your warning, test beforehand, do not use near flammables, etc. you're smarter than that since you're on PV after all). 200 or 300 watts works well. I am not sure if these can still be sourced, esp. in the EU where they were banned in ca. 2012 after I left Europe. The whole rig and a few bulbs might cost ca. $100. To control the spill get some duvateen black cloth (fire retardant) drape it on the ball and use clothes pins to hold it. more ex: http://www.filmtools.com/lantern-lock-china-ball-system.html

There are more modern versions of this. Chimera even makes a"china ball" out of more robust material. http://www.filmtools.com/ch30chla.html

Discussion on DIY here: http://www.talkphotography.co.uk/forums/showthread.php?t=264763 A system using FL here: http://rebelsguide.com/forum/viewtopic.php?t=2785&sid=bf73d2072491d1c1f2d86362ee3c3717

If it sounds too DIY for you, know that Hollywood used this method for years. Just go all balls in and rock it. The light output is really nice.