I am looking into building a library myself and have stumbled across this product:
http://www.southern-astro.com.au/php/software/dfm.php
If you are using CCDSoft or MaximDL, this little program integrates nicely and can automate the entire library building process for you.
The only thing that strikes me on this site, at the bottom it mentions that he has a dark Library for Ha, and RGB???
Why the hell would you need a dark library for those. There is no light passing through, so the filters make no difference, that's why its called a DARK.
I certainly dont have an explanation for this or do I find it logical.
Cheers
Mark