New day, new app in Cydia: LastApp. LastApp is developed by the same guy that did Backgrounder and Kirikae, and it will let to switch between any two apps on your device.
Once installed you must choose and activation method via the Activator preference pane in Settings.app . If you have Backgrounder installed, you can optionally set the current application to background upon switching.
You can find LastApp for free in Cydia, via BigBoss repo.