I know that EMC has an approved host bus adapter (HBA) fibre channel card
for AIX and RS6000. I just can't remember what it is, but if you can, check
the EMC Open System Support Matrix (OSSM). I would guess that it's single
and multi mode capable, and even though it hasn't been tested in the RS6000
labs, if it's approved in the OSSM, it's been put through it's paces, you
can rest assured.

Also, if you have a SAN, you can use an E port from switch to switch to
extend the fabric out to a remote site. I know most switches are single mode
E port capable. Even a little Gadzooks or something similar will connect to
a remote Gadzooks by single mode E port. Then you can run a multimode from
the switch to the server.

BTW, I'm not current with EMC, but the OSSM used to be a coveted
publication, and only available internally to EMC. You might have to call in
a favour, or ask an EMC person to check for you.

Hope that helps,

Kevin.