A new Jailbreak tweak MessageSwiper, which makes it possible for you to switch between conversations in Messaging app with easy swipe gestures.
After setting up this useful tweak, you can switch easy to the next conversation by tapping from right to left or swapping left to right. And You will not bother to go next conversation by pressing message button and then tapping next conversation.Based on Cydia information for app, by long swipe to right you will directly switch to conversation list, but I am not sure about it you may try this.
A very popular app known as biteSMS is also works along with MessageSwiper and not supporting Whatapp, nevertheless, the designer has claimed that in next update he will swipe gestures will be added with Whatsapp let see how he could do it.
It is to be noted that to activate the gestures you need to turn on the Custom Swipe Settings by toggling in the Settings app
Go to Settings then MessageSwiper -> Custom Swipe Settings? On/Off toggle) and then respring the device.
One should feels so easy to use gestures app and i am very surprise that why such a good tweak arrived so late but i hope that in iOS 7 the Apple will also consider this to message apps.
MessageSwiper is almost free on Cydia. Check the download link below to install it from Cydia. And I hope you will really enjoy it.
Download MessageSwiper (This link will only work on jailbroken gadgets)