Someone beat me to it, technically, but here it is, anyway:
SH Crystals Pack v.1.0. (
http://www.pcgamemods.com/10530/)
DESCRIPTION
This is a collection of unique color crystals. When used in a normal (single-bladed) lightsaber, they will transform it into a double blade that can be wielded in one hand.
Such lightsaber staff will give you bonus Master Flurry feat, but also Attack Penalty -2.
Additional Info:
second blade won't give extra attack per round.
all sabers are fully upgradable
unlike similar mod(s) this mod won't affect normal double-bladed sabers; it also doesn't suffer from equipping issues.
crystals will have no effect on short sabers and regular double-bladed sabers, other than changing their blade color.
features additional blade color: Teal (mix between Cyan and Viridian)
features bonus short lightsaber
These items can be either obtained through cheats (more info in the readme.txt) or..
can be purchased from salvager woman Daraala in Jedi Enclave Courtyard on Dantooine. This will, however, only work if you haven't previously been in that area.