This needs to be configurable somehow. How about using including /etc/motd in the welcome message and include a 'last login message'? 
Example:
```
Welcome to Ubuntu 12.04.2 LTS (GNU/Linux 3.2.0-34-generic-pae i686)

 * Documentation:  https://help.ubuntu.com/

  System information as of Tue Jun 11 20:31:28 CEST 2013

  System load:  0.0                 Processes:           84
  Usage of /:   25.4% of 287.52GB   Users logged in:     0
  Memory usage: 36%                 IP address for eth0: 192.168.1.112
  Swap usage:   0%

  Graph this data and manage this system at https://landscape.canonical.com/

No mail.
Last login: Tue Jun 11 14:14:35 2013 from 192.168.1.157
```

Actually since WELCOME is a class variable you would want to find some other way to include this welcome message dynamically.