Shortly before the Torah reading, as people are coming back to their seats from Hakafot, we ask that anyone who would like to come up to the Torah take a card. The cards are handed out and have names of important women in Jewish biblical and Rabbinic (to place it in an era) history. (e.g. Sarah, Rivka, Rachel, Leah, Miriam, Esther, Devora, Beruriah – that may be it). The groups are then called up by the name of one of the women – "Will everyone in the Leah group please come up."
We also have some single aliyot (the first "round" of reading) as honors for active participants. With these groups, we avoid the "who wants to come up next" issue, and even the issue of having to tell someone whether you want to come up or not. Just take a card, or don't. If you really want to be with someone in particular, you can trade cards around (collect and trade with your friends!). Something like this could work during the year as well.