The only X58 board out there with an Intel Ethernet solution is Intel's own DX58SO. ASUS, EVGA, Gigabyte, and MSI are all selling high-end boards with these lame Realtek and Marvell Ethernet solutions (though ASUS seems to use Marvell for higher-end boards like the Deluxe, and Yukons are a little better than Realtek IMO).
But seriously. I can understand cheapo Realtek Ethernet on some bargain basement board, but when you're selling expensive models like R2E or Classified (both around $400) I'm very sure you can afford to spend a bit more on a quality NIC. I've got a P6T SE which is a lower-end X58 board and I can kind of understand their use of Realtek NICs, but what about the Deluxe? Or the R2E? Intel NICs offer higher throughput, less latency, and less CPU utilization (though that's not really what I care about these days).
But seriously. I can understand cheapo Realtek Ethernet on some bargain basement board, but when you're selling expensive models like R2E or Classified (both around $400) I'm very sure you can afford to spend a bit more on a quality NIC. I've got a P6T SE which is a lower-end X58 board and I can kind of understand their use of Realtek NICs, but what about the Deluxe? Or the R2E? Intel NICs offer higher throughput, less latency, and less CPU utilization (though that's not really what I care about these days).