I have practiced mounting the bike with various skirts, and have found the shorter ones work the best. I'm not sure I'd want to wear a longer skirt for fear that the fabric may get caught in the chain, or a wheel. My only apprehension with a shorter skirt is I'm concerned that should a gust of wind hit it just right it will fly up and create an embarrassing flash. Granted, I do wear underwear, but still, I do not want to create an incident that would damage the image of men who wear skirts... Our society (or at least my local society) barley tolerates it as it is.
The simple solution would be to purchase a women's bike. And you all know me... I'm quick to embrace anything of the opposite sex, but I have somewhat of a sentimental attachment to my bike as I've had it for a long time, and it's sort of a "cool" bike to me, what with it's red frame, chrome fenders, and white wall tires. I suppose I could hunt a women's bike of a similar design, but it still won't be my old original, and I'll feel like my old bike "misses me". Sounds silly I know... but there are a few things in my world that actually mean something to me, that bike is one of them. We've shared a lot of memories together. It's like an old friend.
I'd even resort to wearing short pants (trousers) to bike if need be... but OH how I LOATHE the idea wasting a beautiful warm Saturday in anything resembling trousers!

I'd like to entertain alternative suggestions.... and/or stories of your biking in a skirt experiences...