Hi,
I've been using the Unity engine for over 2 years and have experience with gameplay programming, UI, inputs, shaders, implementing plugins, data serialization and more. I worked on a match-3 type game that can be seen in my freelancer portfolio. I'm currently working on a 3d jrpg style game, I can send you some samples if you contact me.
I'd like to discuss the scope of what you want implemented; I'm not sure if you just want the fundamentals of the gameplay (pipe filling, connecting, win/lose state detection) or you are looking for a more complete game. Please contact me so we can discuss the exact scope of your project further.
Martin