You'll want to check the Rubinius test suite. I'm not sure what they're up to lately, but I'm guessing over 10k at this point.
JRuby is using a combination of the Rubinius specs, my own personal, unpublished test suite called 'ruby_test' (at just over 7k tests at this point), BFTS (basically abandoned, the authors are now part of the Rubinius core team), and whatever the JRuby core team decides to add. It may seem a strange mix, but it's actually beneficial, as each group seems to have a different testing style that's mutually beneficial.
You might also want to talk about maintainability because Ho. Ly. God. the Perl test suite is precisely the sort of thing people are talking about when they refer to "the big ball of mud".