Working together with James McPherson, I've been able to get a driver for a really nifty device from DDRdrive -- see here -- working with OpenSolaris.
The device itself has interesting applications -- but I suspect the real killer application for it is in use as a "Logzilla" (ZIL) to accelerate synchronous write loads with ZFS. The only limitation on performance is the software and the single PCIe lane. (We're really right up against the PCIe single lane limit.)
From the driver perspective, its really interesting because it works with only modest changes to blk2scsa (which I'll be integrating into Nevada soon). The driver itself is tiny -- only about 950 lines of code. Its proven to be a great validation of the concept of blk2scsa -- while I never intended blk2scsa for use with high performance devices, I'm ecstatic that its as performant as it is. (Sorry, I can't post performance numbers here -- at least not yet.)
If you already have one of these devices, and want to test it in a non-production environment running OpenSolaris (no Solaris 10 yet!), please drop me a line. I'm willing to work with a few people to get some more testing done.