Here’s my build, at Level 61:
http://bl2skills.com/assassin.html#505001500055050105415050310000
It’s primarily a gun-based Zer0 build (unless absolutely necessary, all weapons are exclusively of Hyperion make). The main weapon – until it gets to the need to replace it, is either the Interfacer (shielded/armored enemies) or Heart Breaker (unshielded fleshy enemies). I always keep an SMG as a backup, a Pistol as a sidearm, and a Sniper Rifle for the big game – although with the Interfacer those moments are few and far between, for instances like B0ring the BNK-3R.
Melee is incorporated due to the fact that aside from their Sniper Rifles, Hyperion is really geared toward constant mobile combat. Hence is why stuff like Killing Bl0w, F0ll0wthr0ugh, and Execute are used in the build.