Tools for TMX

As it is now quite easy to make lots of large TMXes with Bitextor and other tools, it would be good to have some tools for processing them. There are various things that it would be useful to do. For example, given a TMX file:

• strip out translation units for any given two languages. Bitextor and other tools generate TMX files with many possible combinations of languages, it would be good to be able to say, for a file of "no is en da sv", just give me all TUs which are "en-da".
• strip out duplicate translation units. Kind of like a uniq for TMX.
• sort the file by: line length, language, etc. sort for TMX.
• trim the file of dubious TUs — very short translations of long segments, very different punctuation, etc.