I chased around the Arapahoe/McCook area of NE yesterday.  I caught several wallclouds from several different  mesos that tried pretty valiantly to put a tube down.  I did see what I believe was a pretty good gustnado N of US6 as I drove toward Indianola.  The first pic was shot from N of Arapahoe, looking approx WNW:
 
(Click for larger versions)
When I arrived in Indianola, I called Goodland, and the conversation went something like this:
Me: "There's a cone descending from the mesocyclone just N of Indianola"
GLD: "What county are you in?"
Me: "Red Willow....well, now the cone is gone, but there's another w/c under the meso WNW of that one" (See next pic to see what I was seeing at that point in time)
GLD: "What's the name of that town you're in again?"
Me: "Indianola.  Oops, well, now the w/c has lifted from the meso N of McCook, but there's another one dropping from this one here.  Well, I better head over to McCook so I have a road south.  I'll call you back if I see anything else to report..."
 
After arriving in McCook, I got this lightning illuminated w/c:
 
Then I headed S of town and snapped these pics of the mammatus at sunset:
 
 
Funny.  After all the discussion in the "Extreme Photoshopping" thread, I noticed that those mammatus did NOT look anything like that, yet I was unable to remove enough of the orangish tint to those pics to make them look like they did in person without just totally ruining and washing out all the color in the pics.  Yeah, I 
reduced much of the saturation, but those pics still appear way more orangish than the mammatus really did.  Well, I don't have a very good camera nor good editing software...
Bob