iSCSI boot ... root?

Is it now possible to boot from iSCSI?  I'm not talking about an iSCSI
controller, but with

pxe -> dhcp -> tftp (loads loader) -> (something) -> boot (mounts root from
iSCSI)

... now I recall getting stuck on both "something" and "boot" last time.
AFAICR, loader doesn't understand iSCSI ... so if your ethernet card
doesn't make something look like a BIOS disk, you're sunk there.  Obviously
the kernel can handle nfs and the loader can handle nfs or tftp, but it's
expected that the "root" is the same "root" that you're accessing at the
"something" point.

I was going to try to work around "something" when I realized that the
previous iSCSI control stuff wouldn't allow boot parameters to be passed in
any logical way, so I gave up.