9/16-18 UNF Thread to 1/2" HiFlow barb.
And yep, the compression fittings you're after basically aren't available as far as I know. You'd need to use regular 90degree barbs, then get some Pithon Hoselocks to add to them to make them into compression style fittings.
http://www.pi-thon.com/products.htm
However, Pi-Thon are notorious for not responding to e-mails. I've been trying to get their products for months with no success.
Ideally for the look you sound to be after you'd want black nylon 90deg hosebarbs with black anodized pithon hoselocks.