You guys beat me to suggesting Paganini (Mainly caprices, opera fantasies, and variations for "harshness", but his 6 violin concerti are absolutely wonderful; he was not only a virtuoso, but a brilliant, inspired composer, imho) and Ysaye (I really love the Shumsky recording of his sonatas, and I always get a kick out of that homage to the Bach Partitat #3). You should also look into more modern composers like Schnittke. His concerto grosso 1 played by Gidon Kremer is the first thing that came to mind when I read your post.
Have a looksee.
It's a personal favorite of mine, call me crazy, and I know it's a re-release. But actually, if you want crazy violin, look into pretty much *anything* that Kremer does, but carefully, because there are some bad apples among his releases.
You could also look into some Prokofiev. More traditional and there's definitely a mischievous quality to some of his works.
Unless of course you want something crazy in the sense of La Ronde des Lutins, or a lot of Sarasate's stuff. They're not harsh, but they're certainly awesome, at least in my book. Ooh, and the Khachaturian and Glass concertos. There's plenty of stuff out there, if you're willing to listen.
