It sounds pretty much like you may want Gnome3 as your desktop environment. It's quite similar to Unity, but a lot more customisable.
It gives an integrated top bar like Unity, with the menu options. There's also plenty of addons available at https://extensions.gnome.org/ to customise it too.
There's an extension to 'force' undecorated windows too, which sounds like what you may be after: https://extensions.gnome.org/extension/354/maximus/
If you're using Fedora or Arch, or any of the more 'bleeding edge' distros, you may need to do a little hack to get the extension working:
hg clone https://bitbucket.org/mathematicalcoffee/maximus-gnome-shell-extension
cp -r email@example.com/ ~/.local/share/gnome-shell/extensions/
Then log out and log back in again. The extension can be configured by gnome-tweak-tool (which you may need to install, it's in the official repositories).