It does not make much sense to produce a "MetaRaw for Lightroom" product, because there is Adobe DNG Converter available. "MetaRaw for Lightroom" would do something very similar. It would have to convert all raw files to dng or tiff before they can be imported into Lightroom. Unfortunately Lightroom does not support format plugins like Photoshop, otherwise it would make sense to make MetaRaw available for Lightroom.
You can use the free Adobe DNG Converter to convert raw files of unsupported raw files to dng and then import the dngs into Lightroom 6. I know this is not 100% satisfactory, because you either need double as much storage than before, because of the dng files, or you have to erase the raw files and only keep the dngs, which some people may regret in future. Additionally the dng conversion step also costs a lot of additional time.
See also the discussion here:http://www.thepluginsite.com/forum/view ... =42&t=7303