[CentOS] L2ARC (disk caching) for Linux?

First off; are there any storage-centric mailing lists that target
Linux specifically?

Secondly, I'm wondering if there's anything in the works or already out
there similar to Sun's L2ARC[1] for ZFS.  Basically this is a
filesystem (or maybe lower-level) cache for reads, writes that can be
comprised of faster media like SSD.  I think it could make SATA-based
JBOD solutions a lot more attractive from a performance perspective.

Anything out there along these lines already or suggestions on a better
place to dig for information?

Ray

[1] http://blogs.sun.com/brendan/entry/test