Hi,
There is an issue concerning unit conversions in wikitext: https://bugzilla.wikimedia.org/show_bug.cgi?id=235
This one doesn't deserved any attention since a long time. The original proposition was about converting units "on the fly" regarding user preferences. I don't know if it is feasible and/or desirable.
I propose to work on something less ambitious: adding a parser function to provide conversion - maybe in ParserFunction.
The idea would be something like: {{#unit: 1000 ft|m}} => <span title="304m (1000ft)">304m</span>
If I start working on this, will anyone accept to review the code?
Thanks in advance, Sylvain.