ext3 is slower, for the reasons you describe--it has to do everything ext2 does, plus a journal. Since it uses ext2 as a base (not just the fs itself, but the code implementation), it is impossible for it to be faster than ext2.

ReiserFS is totally different. From the benchmarks I've seen, it's generally slower than ext2, but faster than ext3. YMMV.

Update: Minor grammer mistake fixed.

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Reinvent a rounder wheel.

Note: All code is untested, unless otherwise stated