I use Triangle Landscape Supplies which has an office in that area. Last time I bought from them the compost was made from sweet potato waste and maybe turkey farm waste - but that was years ago and they may have a different source now. I usually buy the topsoil/compost blend for my flowerbeds and veggie garden raised beds. It looks kinda sandy but performs better than anything I could ever mix up on my own and getting a year or so without weeding is a plus.

I realize that this isn't what you asked for, and I don't actually have specific knowledge about cattle ranching on that side of the triangle; but in North Carolina, one is never far from some serious rural farming and ranching. Some of these folks need to get rid of their manure. Some go so far as to pile it and turn it so that it becomes compost faster and they sell it at reasonable prices. You just need to ask around (once you get here), and someone will know someone else who can point you in the right direction.

Atlantic Mulch on Ten-Ten Road in Apex sells compost based on the waste stream from a local enzymes manufacturing plant and they deliver. You can read about the different compost formulations they have by going to the Ecozyme website. Family Garden at exit 290 on I-40 also delivers several kinds of bark and mulch. Mulch Masters on US 64 in Apex is probably the biggest supplier of mulch and compost in western Wake County.

Thanks for the ideas - I will definitely look into all those places. Much obliged.