Isoamyl Acetate is the ester responsible for banana flavors in beer. Some yeast strains it comes out far greater than others, especially when fermented at warmer temperatures. The German Hefeweizen yeasts are classic examples of a yeast that throws off a lot of it during fermentation. Though not exactly a style you'd use for Belgian beers.
I'm not aware of any dry yeast that is going to give you more of that character. White Labs WLP570 Belgian Golden ale is one of the Belgian yeasts that you can coax that character out of by fermenting towards the top of that yeasts temperature range. Under pitching the yeast can also help accentuate that flavor as the yeasts produce a lot more esters when they have to work harder for that fermentation!