Imagine running V5e at 600 MHz, a few gigs of RAM, a AGP or PCI graphics card + (S)ATA controller, USB 2.0 and possibly even Wi-Fi. All that on classics for less then half the money NATAMI would probably cost you.
You're grossly underestimating the complexity and costs of the design, development and production of such a HW. You can't just plug the CPU on some board and have it magically running. The limited numbers of boards you'd have to make would bump the price skyhigh. You're not the first one to make this mistake.
I fail to see the point of this anyway: It makes much more sense to run the whole thing inside a commodity HW. There's no way you can beat the bang/buck ratio with a custom design.
