If you're on Face Book, you can contact the breeder, John Starnes, directly from there to see if he knows of other sources.

I was just on their website and it looks like Wayside Gardens has it in stock.

Edited to add: sorry in was Lemon Zest they have, not Lemon Zen.

I bought one from Angel Gardens in Alachua, FL

If you are still looking for this High Country Roses has it back in stock

So cute! It's going on my wish list!

Planted it last year. I'll post pics when it blooms. Vigorous grower with tiny sharp thorns and pretty, delicate B S resistant leaves.