Yesterday at Blockchain Protocol Analysis and Security Engineering 2017, Andrew Poelstra (one of Harry Potter's gang), presented the state of the art on Mimblewimble research. They (the gang) have finally figured how to do lightning network on mimblewimble properly. Mimblewimble will also support some kind of scripting and features like timelock contracts (absolute and relative) and HLTC. the actual blockchain would be pruned down to 2 GB. At the question weather was possible to immagine assets on mimblewimble, the presenter answered:"Definetely yes. possible with a bunch of more crypto".