This German website has Strelitzia reginae 'dwarf' seeds. I have ordered these seeds and others from the site and have had very good germination results. Obviously, the site is in German, but its not too hard to figure out how to choose and buy the seeds you want.

When you finally get to the "pay for order" page and choose "USA" for "ship to", the language turns to English. You can pay with Paypal.

My S. reginae 'dwarf' seedlings are too small to ship or I would send you some of mine.

Here is a link that might be useful: German Website