Try Silverhill Seeds for seed of this and most other SA Iridaceae.

Here is a link that might be useful: Silverhill Seeds

I bought mine from Chiltern seeds. They also have lots of other interesting seeds, but if you're mostly interested in SA bulbs, then you'll find more stuff at Silverhill seeds.

Here is a link that might be useful: Chiltern seeds

Also try Bulbmania. He has a great list. I ordered from him earlier this year and was quite pleased.
Only drawback is you have to do it by e-mail and send a check.

Here is a link that might be useful: bulbs

Also, thebulbman.com although his shipping period will not begin again until june.

wanda