No, I actually don't get much cleavage with balconette styles. Although my breast tissue is fairly "bottom heavy," I don't fall in to the center at all. Even plunge styles are fine, as long as the cup size is correct. I might be wide set... although my underbust is literally less than 30" and "wide" is a relative term. I don't naturally have much side projection and look very flat and non-hourglass from the front. I've also rarely had a problem with a bra's center gore being too wide. But I know where you're coming from - I hate the feeling when my breasts are touching. I started wearing a sleep bra mostly for that.
Balconettes tend to have really good structure to them, that really lifts and shapes; look for vertical seaming for the most support. I also get ones that have a single panel from the strap to the underwire on the outer part of the cup. The Marcie and the Kali have that type of construction. Different models have different cup shapes. Some are more projected and some are round like a t-shirt bra. The discontinued Lily is very round.
http://www.herroom.com/cleo-by.....-bra.shtml
http://www.herroom.com/cleo-by.....-bra.shtml
It's really going to be a personal thing! How you want the bra to fit and feel will be different than me, and how any given bra will fit you will be different. It's no longer being updated, but I found the blog Bras I Hate to be incredibly useful. I learned so much from reading the posts on all the different breast shapes and how differently bras can work. [I just saw she's got a new blog! Yay, more reading to do!]