Set the date and time in menubar to be in a specific format

I want the menubar to display the date and time in the menubar as follows:

2012-10-03 09.12.14

which translates into Year-Month-Day 24hr.min.second

What I've tried:

Gone into System Preferences > Date & Time > Clock

Selected: Digital; Display time with seconds; use 24-hour clock

This gets me close to having the time right.

Gone into System Preferences > Date & Time > Date & Time > Open Language & Text > Formats > Dates > Customize

Changed every date format (short, medium, long, full) to have yyyy-MM-dd

Gone into System Preferences > Date & Time > Date & Time > Open Language & Text > Formats > Times > Customize

Change every time format to kk.mm.ss

The problem:

It still shows the date like:

3 Oct 13:19:12

in the menubar.

Details:

I am running Mac OS X 10.7.5

Any help or suggestions you can give, much appreciated!

Solution 1:

There is a free app called Day-O that is flexible and can do what is being asked: https://shauninman.com/archive/2016/10/20/day_o_2_mac_menu_bar_clock

Solution 2:

Whilst I'm not sure this is possible with the built-in menubar clock formats, you can acheive the format you require using the excellent iStat Menus ($16, but it does have a 14-day free trial).