Actually - I haven't gotten much feedback on it, so there may be bugs I haven't noticed, but I ran the xml files through "winmerge" and have, I think, setup a mod to run DL and DA under the Twilight Engine.
I do recall hitting a bug with the "GalcivII_Twilight_Techtree.xml" not working right, but since it was just a 'cheat' techtree that resulted from my figuring out out stuff worked, it's mostly for reference purposes and I haven't bothered fixing it
http://library.galciv2.com/index.aspx?m=806
Just drop the two folders in your mod folders and select the appropriate tech trees for the campaign - if you have any bugs, yell at me.
Jonnan