I couldn't find anything that did exactly what I wanted, and my spreadsheet was getting overloaded, so I wrote a small app for organizing offers/cards/churns and keeping track of where I am on my spend reqs. Shows me how much I have to spend, how much is left, status and dates of all apps, what rewards I'll get, etc.

For actual expenses and budgeting, I just dump the cards into Quicken along with my permanent accounts, then close/hide them once the spend is completed.