[@Nevix]

not as a starting weapon dios slicers are made by having to hunt the brachydios which is arguably one of the most powerful monsters. Your aloud to get weapons and armour like that in the future but you have to start with weapons your hunter could have acquired. Duel blades themselves could be things like matched slicers, jaggid shotels, matched hatches, pretty much anything that is under a 180 starting attack power. 
You can have your character customize his or hers existing blades though, like painting it or adding to its appearance to make it really fit that character and your weapons can and would have to be upgraded and changed to eventually being able to get a dio slicer set. The tougher things you kill, the better weapons and armour you get. 

You can find every kind of duel blade set that have been brought to monster hunter. Anything that is 180 or under is fair game as a starting weapon.http://monsterhunter.wikia.com/wiki/MH3U:_Dual_Blades_Weapon_Tree