OOOh, I hope you do decide to get a little boy - the boy/girl combo is sooo perfect. Oscar is my 'golden boy' - and I can't help but have a little soft spot for him as he was my first puppy.  I think Coco would love having a little male buddy around - and if she IS really submissive, then I would definitely recommend a male over a female (they call them bitches for  reason right? 

 )