Why?  Would you expect the konsole window to be automatically moved to the current desktop (like KMail)?  I understand why KMail is unique (due to reading/locking/etc of emails).  I don't think it would be viable for konsole.

What I have in mind is the behavior of konqueror: if you run something like "konqueror openURL ..." and there is already a konqueror window on the active virtual desktop, you get a new tab. If there is no konqueror window on the current virtual desktop, you get a new window.

This way you can simply define a single keyboard shortcut and it automatically does the obvious thing. To some extend, this behavior can be emulated with konsole via dcop scripting, but not entirely.

I should have been more explicit in the original report. To sum that up, what I have in mind could be paraphrased as "optionally reuse active konsole instance à la konqueror".

*** This bug has been confirmed by popular vote. ***

Under KDE 4, Konsole will be a single-instance application, but that is not actually what this report is asking for.

This report is asking for a single-window application, which is slightly different. 

*** Bug 83027 has been marked as a duplicate of this bug. ***

Would this allow one to write a script that opened multiple sessions (tabs) in a single Konsole window, and execute ssh connections to different servers using the -e commandline option?

For instance, it'd be really nice to be able to do something like the following:
#!/bin/sh

konsole -e nano -tabtitle "Local"
for I in someserver1 someserver2 someserver3
  konsole -e "ssh $I" -newtab -tabtitle "$I"
done

Then one could set the Local tab to "Send input to all other sessions" and manage multiple servers.

Currently, I can load console with a bunch of sessions running, with named tabs, but I have to manually run ssh from within each tab.  :(

AFAICT, there's also no way to do this via DCOP, as one can't tell a session to run a command.

Cheers
Freddie

Implemented in KDE 4 using the KUniqueApplication framework.