There seems to be a high demand, so I've created the first beta version of a file type for MXLIFF Files.
You can download it here (note that it is not signed, so you will get a warning every time you open Trados Studio):
https://github.com/jessegood/Leo.FileTypeSupport.MXLIFF/releases/tag/v1.0-beta
I've tested it several times, but it would be great to get some feedback from actual users!
If everything goes well, I hope to publish this to the appstore in the future.
1. It should be able to handle various memsource tags, such as {b>, <b}, etc.
If you find a tag it isn't handling let me know.
2. If it doesn't find a translation in the target, but a translation in the <alt-trans> tag, it will display that in Trados.
3. Comments are supported, however, Memsource seems to only allow one per segment, and doesn't have the multiple comment feature like Trados. Currently comments made on Trados segments are supported, but if you have multiple comments on one segment, I just combine the text into one.
4. I've tried to map, m:confirmed, m:locked and m:score and various other attributes to the matching ones in Trados.
5. I've tested that the generated file can be read by the Memsource desktop editor, but I don't have a cloud account that allows uploading, so it is untested for uploading to the cloud.