qemu performance emulating sparc64 (UltraSPARC II) running NetBSD

What are the current best practices for, and performance of, emulating an UltraSPARC II server (e.g. early Sun Fire V125, V215 - no graphics or X11 required; just processor, RAM, disk, and Ethernet) on a relatively modern AMD Opteron (e.g. X3421) or perhaps some flavor of Intel Xeon processor? I’m definitely going to be running NetBSD on the emulated system.

Emulation always imposes a cost on a per-instruction basis, but if the modern host processor is fast enough, emulation can beat the old silicon. Is qemu there for sun4u UltraSPARC yet?

My need is slightly pressing: dying ancient SCSI disks, and really don’t want to replace them - rather virtualize the whole system as a path forward, but while avoiding binary data (big endian to little endian) conversion.

	Erik