Okay - some thoughts on the subject:
- I am from the school of thought that men and women should be able to cross gender lines and wear or carry whatever they wish without social restriction.
- I am also from the school of thought that especially when crossing gender lines, in terms of how others will perceive the action, there is a slightly higher burden placed on the carrier/wearer to make sure the item looks tasteful in context. For instance, while I feel that there is nothing WRONG with a man wearing a pair of high-heeled black Louboutins, they probably are less aesthetically sensible than say, a pair of Chanel shields with crystal logos.
- In terms of a man carrying a speedy bag, there's nothing unkosher about it. I would recommend considering the size in terms of proportion to one's body. Most men probably look better with a larger speedy (35 or 40) - it's not just about your height. I think a 5'2" guy as well as a 6'6" guy can both pull off the larger sizes - but in proportion to your torso, the bag should make sense. As I am very tall, I necessitate at least a 35 - and as I am not skinny, a 30 is definitely not happening. In proportion to my horizontal stature, I'm pretty average, but if I weighed what I used to, I'd have purchased a 40. There's no formula for this and it's about what you're most comfortable with and look best with.
Also, one must consider that not all Speedy's come in the larger sizes (35 and 40) and as of now, only the mono comes in a 40. I ended up with a Damier 35 and may have purchased a 40 had it existed, but the Damier is my canvas.
Be yourself. Be confident in it. That's far sexier than following rules that other people made up for you before you were even born.