I've seen several patterns for this sort of split skirt and a number of places online that sell them premade. I think the finished version of TV299 blows the competition out of the water.
This is the TV pattern that I had the most trouble with, but the problem was not due to any flaw in the pattern, but rather to a printing error. The pattern designer was very supportive and fast with advice to help me salvage my project. She also offered to replace the pattern for free. I will admit that I was not so happy about the error, but suprisingly the outfit still turned out beautifully.
I would also note that this skirt requires a lot of buttons, 20 in all. So be prepared to spend a large chunk of time dealing with button holes and buttons. I didn't find this task too bad, but making machine buttonholes always makes me a bit twitchy. I can do about 8 button holes per major sewing mistake, so I've gotten pretty good at ripping them back out. Hopefully other folks won't have this sort of problem.
I still need to properly hem the bottom edge up an inch or two. I may need to remove a button or two at the bottom to get it to work, but I really want the bicycle length, so I'll fight my way through it.
I would recommend this pattern, but only to an intermediate seamstress. The instructions are complete, but some of the descriptions for finishing the front waistband and the plackets are a bit unclear. I spent about 15 minutes reading the instructions over before I had everything worked out in my head. After that the only nitpicky part was ironing in the pleats and even that wasn't too bad.