The Abercrombie and Fitch model is nice, but way out of my price range. It still appears to be authentic though.
However, there's a second sundial cannon for sale right now on EBay in the mid 4 figure range. It is fairly crude, but to my eye, it looks faked.
http://www.ebay.com/itm/c1780-Noon-Day-Meridian-Bronze-Cannon-Sundial-On-1696-Limestone-Plinth-/271107009725?pt=UK_Antiques_Architecural_RL&hash=item3f1f3cacbd It's supposed to have been out in the weather. OK, I can buy that, but if one looks at the gnomen (wedge shape fin) that tells the time, it is all corroded. However the screws and the surrounding screw holes are simply too clean and well defined. Judging from the weathering of the limestone base, those screws and screw slots should have been totally corroded over with gunk. They are simply too clean and crisp.
Also, stylistically, none of the components seem to match. What they are calling "Rococo" which is the fancy decorative dresser drawer pull stuck on the side looks totally out of place. Personally, I think this thing looks like somebody simply took some old pieces of this and that--put them together and simply faked some of the aging.
IMHO, It might be worth $50 just to stick on a pedestal in the garden, But otherwise, it's a piece of crap.
Of course that's just my opinion and you know what your proctologist says about opinions.
Cheers