Keep your eye on ebay.com.au, as you might find a seller with these seeds ... eventually. If you're willing to buy from an overseas supplier (you don't need an import permit for a small quantity of these seeds), I can recommend banana-tree, which stocks them. (GardenWeb won't let me post the URL, so just add a '.com' to the hyphenated name.) Only problem is that they've increased their minimum purchase order (to US$15), so you might want to get together with other gardeners and make a group purchase. They have a great range of seeds on offer.
Alternatively, ask your local nursery. Although they might not stock it, they might be able to order a plant for you. A local supplier is always better than an overseas one, so long as you can find one offering the plant you want.
islandgirl
cestrum