I just found this spreadsheet and was given permission to post it for everyone. Its downloadable and has options for 10 or 20 debts. It also has a place where you can change the amounts for lump sum/extra payments made and it will adjust for you. The only downfall to this spreadsheet compared to others is you are unable to put in 0% interest promos before interest kicks in if you are paying highest interest first rather than lowest to highest debts.
http://www.vertex42.com/Calculators/debt-r...calculator.html