Well, if you're looking for a source of multiple languages comparisons, the old "I Can Eat Glass" project where someone solicited a bunch of translations (quality naturally varies) for the phrase "I can eat glass, it doesn't hurt me", seems like it may be of use.
The original seems to be down, but here are three sites where people have
mirrored and/or added to the languages presented (including using the original language scripts instead of transliterations).
Personally, I'd say that if written in the Roman alphabet instead of Canadian Aboriginal Syllabics, Inuktitut (which I used to be minorly interested in learning several years ago) seems like a pretty good candidate for length, given its agglutinative structure and the circumlocatory nature of some of the phrasing required due to its vocabulary limitations.
Tamil and Burmese also look to have impressive character counts, based on the length of their sentences as written in script compared to the other samples.