John,
spot color is a great idea creatively. Only "problem" is that Dog News charges $250 per B&W page non-preferred pages non-bleed. Full bleed is another $100 and one additional PMS color is $125. That quickly gets you into the realm of a full-color ad which starts at $600/page.

When folks come to us asking for advice for Dog News, we recommend B&W (they have traditionally printed B&W pages better than 4-color) but, if they are prepared to pay for a full-color, full-bleed ad, we try to talk them into B&W, full-bleed with spot color because it really does stand out from the other advertising.

Jim