I'm surprised this hasn't yet been made, but I wanted to start a thread for everyone to share their vaults!
I'm still working on my first vault, but here it is: http://i.imgur.com/X0dFibl.jpg
I'm currently at 173 dwellers, 50 of which are exploring.
I'm having some major internal battles with how I want my finished vault to be laid out. It's so expensive removing and rebuilding rooms... there REALLY needs to be a way to edit room locations.
Also, as someone trying to expand slow, I send all my new advlts out with high luck gear and 25 stimpaks and radaways. This keeps the overwhelming number new dwellers busy without dragging down my happiness because they don't have jobs, plus it gives me something to do with my surplus of stimpaks and radaways while assuring I always have tons of gear to outfit my vault with. All my dwellers have outfits with +3 in their respective roles or better and guns with 5+ damage or more. I stopped trying to keep ALL of my women pregnant as it's a nuisance shuffling dwellers around. when you have a room full of pregnant women. I just keep dedicated pairs of women and men in the bunkers and they keep producing babies faster than I can even put em to use. Having all your women pregnant at all times is a real pain in the ass honestly.