With most Android devices, its not that 720p is the limitation, but some of the advanced settings used to encode the video to H264. Things like the profile (main, baseline, high) as well as Cabac, Reference frames etc are not supported fully, so you end up with either unplayable files or stuttering playback. Of course, the audio format from your files is also a big factor. 5.1 audio is problematic, and will either result in hissing or no audio at all.
Players like Dice, Rock, Mobo can make those files play, however, because they use a software-based decoding engine, rather than the hardware, the processor speed as well as the optimizations used in their codecs become a major factor in playback as well.