here's my 4D lantern mod. It was quite involved, but I'm sure you could do it more simply.
I second the NW/WW and high CRI options. CW LEDs really make you all look like zombies. I like mine much better now with the Nichia 219 in it. It's had a bunch of use and the only thing I'd do would be to add a velcro strap to the battery holder as sometimes cells will fall out if it's dropped or jolted. You could easily add a multimode driver in there too, but I've never felt the need.