The iPhone and iPad are almost identical. There are plenty in the community who have made the divide between the products. Even if you can manage to get coverage on a site that blends iPhone/iPad coverage that is just fine (I've had this happen, sales went from around 40 to 180). I also consider it a huge benefit to get my brand in front of iPhone only users. It's likely that they'll know friends with an iPad and/or they may become a fan (fb, twitter, newsletter) in anticipation for an iPhone version.
iPhone and iPad coverage is hard in general. Getting my latest product out there has been a huge pain. Originally released on iPad, I had little coverage. I have yet to get coverage on the iPhone, though, it's still early. It's incredibly important that you spend time building relationships with editors, but that's far easier said than done.