No that's really nasty. Spike and Dawn have a type of Brother sister relationship, there is nothing sexual au romantic about it. Sometimes shippers creep me the hell out. Not to mention that Dawn is 14,15,16 on the onyesha while Spike is 20 something (Or 120, depending on how wewe like to look at it). So pairing him with Dawn would be like calling Spike a pedophile which is pretty unfair to his character because he certainly wasn't one.
From my perspective, Spike and Dawn would definitely go together very well as a couple. And I can see Spike looking on and smiling proudly while Dawn shows off her elegant dancing skills (since Dawn did state in one episode that she loved to dance). Besides that, there are a lot of fanfics about the pairing known as Spawn (Spike/Dawn), too — especially on fanfiction.net, of course. :)
