Now that you mention panniers, do you have hard luggage? How about mounting a tube on the front of one of the sidecases (if you're not carrying a passenger), or maybe on the underside. Still not as far forward as tank panniers, but better than the topcase or the usual DL650 tool tube location.
And depending on what tools you're carrying, you might be able to use a pelican case or similar, which is easy to lock and a lot tougher than the average tool tube.
2010 Triumph Tiger 1050se
2009 DL650A - sold
2005 DL650 - dearly departed
"I am enthusiastic over humanity's extraordinary and sometimes very timely ingenuities. If you are in a shipwreck and all the boats are gone, a piano top buoyant enough to keep you afloat that comes along makes a fortuitous life preserver. But this is not to say that the best way to design a life preserver is in the form of a piano top. I think we are clinging to a great many piano tops in accepting yesterday's fortuitous contrivings as constituting the only means for solving a given problem." - R. Buckminster Fuller