As far as I know... to change the size of the Panel in Unity you should edit the Source Code.
NOTE: In this example I'm running Ubuntu 12.04 with Unity 5.20.0
Download & Edit Unity Source Code.
1) Make sure you have enable the Source code repository
- Open Ubuntu Software Center.
- In the Menu Bar choose Edit -> Software Sources. Click to enable "Source code repository".
- Just in case I use the "Main Server" to Download.
2) Open a Terminal and install the necessary packages.
sudo apt-get install build-essential
3) Install build dependencies.
sudo apt-get build-dep unity
4) Create a folder to download the source code.
5) Download the source code.
6) Edit the the files "PanelStyle.cpp" & "PanelIndicatorEntryView.cpp"
Search for the line "63" and change it.
eg:(In my case I changed it from 24 to 42)
Search for the lines "208" & "215" and change them.
eg: (In my case I changed them from 22 to 24)
pixbuf = gtk_icon_theme_load_icon(theme, proxy_->image_data().c_str(), 22,
GtkIconInfo* info = gtk_icon_theme_lookup_by_gicon(theme, icon, 22,
pixbuf = gtk_icon_theme_load_icon(theme, proxy_->image_data().c_str(), 24,
GtkIconInfo* info = gtk_icon_theme_lookup_by_gicon(theme, icon, 24,
7) Go to the "unity-5.20.0" folder to build the deb packages.
dpkg-buildpackage -rfakeroot -uc -b
8) Now you can install the deb packages.
9) increase the font size from 11 to 12.
gsettings set org.gnome.desktop.interface font-name 'Ubuntu 12'
10) Finally you can logout and Login or Restart to see the changes.
Hope it helps.