Here is a little tutorial to build your own Apple Lightning Mini Dock (for your iPhone 7).
I my self was really annoyed by Apple removing the Headphone Jack because I am using it every day. Also while charging...
You definetly need an ORIGINAL Apple Docking Station for the iPhone 5C and a 3D Printer.
Be careful, as the original dock only has a Line Out port, the volume cannot be controlled by the headphones or iOS.
Step 1: Disassembling the Apple 5C Dock
First remove the soft cover from the bottom (with the Apple Logo printed on it).
Then remove the cover with a screwdriver (there are little slits around the case).
Now Remove the metal weight to access the circuit board. While removing it gently with a screw driver, be careful not to detach the small connector cable (Lightning Plug to circuit board).
You should now have something like shown on the photo.
Now gently form the flat connector cable to a "S" shape. You'll need this step for the board to fit better into the case. Connect the two flat ground cables to the plug.
Step 2: Printing the Case
The STL Data of the case is hosted on thingiverse: Thing
You can print it with fast settings (so did I) and it should work.
Step 3: Inserting the Circuit Board Into the Case
Insert the Lightning plug first and after it the circuit board. If everything is sitting flat in the case, push the both connectors (Lightning and Headphone Jack) into their appropriate holes in the case (so they snap in).
Step 4: Finish Everything
Now your case should look like the one on the picture. You can now fill everything (or just the connector on the bottom) up with hot glue and put the lid on.
This should give you a very small version of a Lightning Charging Adapter with a Headphone Jack.
At the moment there is only the iPhone 6/7 Dock (55$) or the Belkin Rockstar (40$) around. With this solution you should be able to save up to 50$ (compared to a normal Docking station which does not fit into a small pocket!).