I want to make a city builder asset

Hello uniters,
I did many parts of different buildings and i follow a global unit system that scaling will make no problems and easy could be snapped together.
I have only done the top down shooter tutorial, but can me please lead someone in the right direction?
All i do i do from scratch no external materials used (i dont steal).
http://luftbauch.deviantart.com/
The last pics show me testing it out, but this still needs some time to get polished and usable.
I want that my assets are in some sort of library, for example corner_left_type1_basement. /pillar_fill_32_type1
Type stands for different styles of the buildings.
Then you can drag and drop them onto a grid and they will fit perfectly.
In the moment i did only the highpolyversion but i want to bake textures onto lowpoly and offer that too.
Till now i have 137 parts finished (without textures), enough to build two buildings with small variations.
I would like to preconfigure some stuff like one complete floor walkable, one only external(for example).
I hope you can understand what i am talking about with my rusty english, forgive me that.
First i need to finish more parts, but i would also be interested to give later a model away for free to get some feedback?
Perhaps here is a coder that is interested to do the coding part for me with an asset store account and experienced in uploading stuff and advertising. I am willing to share profit, generated through that asset, if i find someone who i can trust.
I am open for suggestions for parts or asset that should be included.
If you sketch out some forms i can integrate that too.
Best regards Stefan

 

Here a suggestion for your city builder.Whereever the user puts the city pieces or buildings it should level the terrain.I believe you should be able to place down many buildings at a time.Then you could rearrange them yourself.While they hug the ground.Making the buildings where you can walk in them is a good idea.

 

Thank you @ hard target. I bet that would be a nice feature, but i have no clue how to realize in unity.
Perhaps you can lead me to a tutorial that i can code the asset by my self like i wrote in my startpost.
Without a nice coder/in i cant realize it like i want.
Some time ago i found something similar in the asset store, but i cant find it again.
He had a nice system there where each floor had a color and each fitting part had the same color, was easy to use.
In the moment i arrange the objects inside Blender with many arrays.
I think noone is interested to drag and drop 50 objects to create a house by self.
If a coder reads that, i would be happy if we could make a deal.
Its really easy to make nice perfectly fitting object with that. Texturing is easy too, because of unit system.
What do you think?

 

Look at this tutorial and you might learn something new.Unity3d - Object placer in play mode.
It is on youtube.