The character study thread for Miles Morales included some discussion about giving Miles a dog. The art included shows an older Miles Morales than was eventually decided upon with a skateboard and what looks like a French Bulldog (or possibly a Boston Terrier): 
 
 
The skateboarding thing, well, it seems fine the way its drawn above, but it kind of makes me worry cause Marvel has had an overabundance of skateboarding black characters before to the point where it's become kind of a joke.  
 
As for the dog, though, I think that's awesome! I'm a big dog person and I'd love for Ultimate Spidey to have a dog. It would definitely say something about Miles. Every interaction would be a potential pet the dog moment for the character, it would allow for potential kick the dog moments for villains, and it could pave the way for Ultimate Pet Avengers! Because Miles is younger now too, Bendis could even show him finding and adopting the dog (out of a sense of responsibility!).
 
Go Ultimate Spider-Dog. 
 
 
Also, what would Miles Morales name his dog? That'd be a big personality sign.

I think the doggy is so cute I could see it being named Spike if the artist decided to keep the dog in the comics.

Miles and Spike the Spider-Hound. I back this all the way.

They could introduce the dog later in the series.

The series is still young. Give it time for Miles to grow.