If you prefer to call Great Danes and Chihuahuas a separate species based on the weak definition of speciation it's OK by me but you should acknowledge that the mechanism which brought about their reproductive isolation and hence their "speciation" was intelligently designed by breeders, no?
The breeders change the environment in which evolution works. So you could call the process guided evolution or something like that.
If the breeders had actually designed chihuahua genes ahead of time and inserted them into the genome, then youd could call it intelligent design. At least that's how ID appears to be used elsewhere.