I dont mess with hyena dipes either, and i havent bought anything new in a very long time. but I have a few black wool covers and some black fitteds. the black fitteds i got are from a local mom, but she has a yahoo group, its called 'spooky kitty collective' i think. I am not sure what type of black my dipes are, maybe they are just terry or hemp terry, though. so that may not work for you.
also, the wool is from 'monster baby' not sure if they are still around or not. I also have some great black and white combo dipes. again, from 'spooky kitty collective' and some from star bunz (like a black and white shiny leopard print) also, I have some zebra stripe diper covers, but you would be hard pressed to find those types of paterns in organic.
you could just buy a dipe for this photo and then sell it if you cant find hemp or organic. I find the black stuff doesnt stay nice, anyway (I have a black fleece cover that was speckled white after one wash) they get so fuzzy with lint, its really really hard to get them back to all black again....
I also had some white fitteds, with black snaps and black serging from sugarplumbaby that i got a few years ago. they are nice.
good luck.