My only concern is that if we were to use tvar|about_1, tvar|about_2 for .../wiki/About, this would appear to translator as
$about_2 Some other text
and they might want to translate it to
$über_2 This text in German
but with plain numbers with would not be the case, so I think we should use them instead: tvar|1, tvar|2 and so on - they are straightforward.
This would mean the same links wouldn't be autoreplaced I know, but they are not so common anyway.
What do you think?