I've found that when I google Pegg/Frost or Bernard/Manny from Black Books, I find great fics, photos, graphics, wonderful comms like this one. I also find a lot of "That's so wrong. He's all FAT and HAIRY and Ewww!" Or weak concessions of "I see the slash, but I can't read it/see it, etc."
Some of these comments have a homophobic undercurrent, but I still find comments like that among other slashers and RPS fans (people with pretty yaoi characters and Tokio Hotel all over their LJ headings and icons) and those comments seemed to be centered around Nick's size and, therein, his level of attractiveness.