Canon 5d3?

I've got a 7d, 550d and also a Panasonic G3 with 14-140 (light and takes good pics which is great for a cyclist, but the EVF is a pain).  I have an assortment of EF-S lenses including 10-22 EF-S (which I may sell) 60mm EF-S macro, 17-55 2.8 EF-S (which I may sell), 15-85 EF-S (almost permanently attached to the 550d), 55-250 (light, reasonably sharp and costs little). I also have 50/1.8, 24-105L, 100-400L, 2x converter (this combo is great for lunar shots), and 135L (I have a sharp eye for used kit).

So what do I do with this heap of kit? 90% landscape, skies, woodland, sea scapes, plus the kind of shots that everyone takes - family photos etc. I print and show them locally. So I come to my question. I am thinking about full-frame. I am sorely tempted to lay down the cash for the 5dIII, but I question how much it would improve my photography. Sure it's great for low light with its fantastic high ISO, but how much improvement would I see in "ordinary" conditions - shots of sunsets and skies?  I have other options; wait for the 6d, or even move to Nikon d800e, or just keep what I have got.

I print up to A2 but could consider getting A1 prints done by a bureau. I am intrigued by the medium format capabilities of the D800e.

I have a fairly decent Slik carbon fibre tripod, but the problem with tripods as they are not portable on bikes (but I do drive too, but I find tripods are a pain in the wotsits).

Sticking with the 5dIII, I am intrigued by the built in HDR capability (although I am amazed at the horrors that sometimes appear from this technique). It certainly compensates for the relatively limited dynamic range that it has compared to the recent Nikon DSLRs.

I will need a wide-angle for the 5d3, and also a macro, which certainly knocks up the cost. Most of my shooting is wide angle on the whole, so I would appreciate suggestions as lenses.

Oh here is my web site http://www.markhbfindlay.com/ and I am on Flickr at http://www.flickr.com/photos/markandstuart , which contains a lot of my photography over the years, including various subjects that I don't often shoot.

Software-wise I use LR 4, which is brilliant, and Photoshop Elements 8 when I need layers etc.

I live in Brighton, UK and suffer from UK pricing for kit, but I have some savings.