CocoaLumberJack is probably my favourite logging framework. Thanks to it's modular nature you can easily create your own log formatters, or in this case create your own loggers. What i've done is implement a Parse "objects"inside of a DDAbstractLogger subclass which enables this ...
I've added in the [[UIDevice currentDevice] name] so that you can differentiate between the devices. You could also sort my messages, method name, file name and line number.
Check it out on Github