Specialized shoes tend to have a roomy toe box.

A note on the Sidis (though addressed in the previous post): I find that the mega sizes add considerable volume in the upper that should help with all but the broadest feet While the footbed is widened and lengthened, the upper feels noticeably larger. I wear size 44.5 regular Sidis ideally. I have one pair of size 44 reg road shoes that are nicely broken in and slightly snug but usable, one pair of 44 reg mountain shoes that aren't as broken in but, slightly snug but usable, and a pair of 44.5 Megas that are just right but feel too big in the toe box and heel to feel ideal. The 44.5s would probably fit perfect in a regular 44.5, but I would probably rather go down to a 44 regular than buy another pair of 44.5 Megas. In a Shimano road shoe, feel pretty good in a 44 (a pair of 44 Sidis without insoles would probably fit about the same, fwiw).