Sourcing perennial grains?

I've been reading about perennial grains lately. Seems like a good thing to grow in my pastures...but where to get them? It looks like all kinds of research and breeding is being done, but I haven't found anywhere to actually buy seeds...at least, not anywhere that is even slightly affordable! We have cows, sheep, pigs and chickens that rotate through 5 sections.
Currently all Bahia Pensacola with a healthy population of dog fennel and beauty berry...north central Florida, hot summers and warmish winters with a few frosts but very little actual freeze. Summer is supposed to be the rainy season but this past one wasn't really.
Suggestions for planting that I won't have to reseed every year?
Thanks!

Which specific grains are you seeking to grow?

I don't have any specific ones on a must-have list. I'm aiming to have self-sustaining pasture that still looks nice (because my husband wants it to be pretty)...if I can get some deep-rooted perennial wheat, oats, rye, clover, etc, we can use a mowing schedule along with rotation to capture water and fertility...we're in what's called "xeric sand hills" so nothing sticks around for long. I'd rather avoid amaranth because it gets weedy quick in our climate.

I feel like if we can get some deep roots going underground, we'll be able to start building up above-ground.

Since you mention it, red clover works well for me.  Of course, it is not a grain.

I'm planning on a couple different clovers so we'll have it mostly year-round. I can get it in 50lb bags locally - grasses also. But I'd like to go above and beyond "normal" pasture...was looking at Kerzna, but it doesn't seem to be available yet. There's a perennial&heirloom grain site up in Canada, but it doesn't look like those varieties would do well here. I might end up having to contact the land trust and see if they would let me test the Kerzna.

hopefully this is of interests to you. I found them thru reading The Third Plate by Dan Barber.

Blurb on the Klaas Marten/ Mary Howell Farm

Lake View Organic Grain

PDF of what Lake View Organic Grain has to offer.

According to Baker Creek, their Rose Red Soba is a perennial buckwheat. I haven't tested it yet myself, though.

Jordan, you sent me down the rabbit hole with those links! I got caught up in reading the website and got lots of future plan ideas...back to the list, now I have to figure out if any of those grains are appropriate for Florida, and if I can source them locally. Thanks!

Ellendra, I'll check into it...love Baker Creek, but have only done veggie seeds from them so far.

*edited to correct auto-correct spelling mistakes and reply to additional comment.