Sword ~100k give or take. I'm not sure if Dadao's are rare drops or not, but I haven't seen many here on guru. 15/-10 is a good damage mod, and the req 8 is highly sought after. Get another opinion I'm not a PCGuru or anything. The 30HP pommel is worth 60-75k as per the price guide. Mods normally don't affect the items price but +30HP will definately make the item more attactive to potential buyers.
Dirks I would say 5k tops. 20% Hexed is getting popular but is very specific in what the person wants to do with it. Again req 8 is perfect and vamp is a nice mod for assns-maybe second best to zealous mod.
Hope this helps, good luck.
PC on sword + daggers
Levi Garett