If you have wide feet you're probably going to have a bit a job finding the right shoes.
I have spent the last couple of weeks researching the subject and trying on all types of shoes and still haven't found the right pair.
I have measured my feet and basically I'm a 7-7.5 (41 EU) length but a 'GX' width (3E US).
The Sidi Mega's are supposed to be an 'E' width although I haven't managed to find a stockist in my area to try them so couldn't comment on them. I have been to 6 different shops in my area and tried loads of shoes from Northwave, Shimano, Bontrager, Specialized and Mavic.
Essentially forget about Mavics, they're too narrow. For all of the other makes I still have to go to a 43 for them to fit my width, the Spesh were comfy in the toe box, but the arch was too tight and they came up the longest (I could get my index finger inside the heel cup quite easily). The Bontragers were also a little tight around the arch as well and I just didn't like them at all. For me the best fit were Shimano R085 and Northwave Vertigo, I very nearly fit into a 42 in both (left foot was fine, but my right foot is slightly wider - bugger). I tried various other styles in both makes, but most were longer/not as wide.
In summary, try as many shoes on as possible because like feet they're all different. Or you could try the Shimano custom fit shoes if you're prepared to pay the £160+ for them.
Edit: I was also recommended Carnac shoes as they are made on a North European last which is apparently wider but couldn't find anywhere local that stocked them to try.
