Personally, my character sheet has to keep track of a ton of stuff. There are 24 base attributes, 10 combat stats, health, manna, ki, equipment and backpack, three types of money. It will also keep track of a bunch of stuff that not everyone will use, like magic and abilities, proficiencies, holdings and buildings, favor from nobles and gods, deity, and occupation. The player may also have to keep track of shop/fort/building inventory, ship hold and supplies, soldiers commanded and supplies, NPCs commanded, political maneuvering, trade ledgers, and plot.
So, what I'd suggest is a form that will allow you to add stuff. Columns, headings, text boxes, etc. Not only do different games have vastly different requirements, but sometimes those requirements change over the course of a game. Set up a handful of "default" charsheets for more popular games like D&D, Vampire, or GURPS. From there, people will make what they need. The best thing that you could do is have a hub for content of some sort, like dffd, where people can upload and rate character sheets. If someone makes a really nice charsheet for Amber diceless or Champions, it could save some people a lot of time, and all they'd have to do is go get it. I know that's a big leap from what you're talking about, but the prospect of the program's abilities are exciting. If all else fails, you can host a website that you continually add new sheets to, and people would get to pick and choose which ones they want.