Another way to add to head retention is to pressurize your drink with nitrogen rather than CO2, think Guiness. This aides head retention as N2 does not dissolve as easily as CO2 in water therefore leads to a longer lasting tighter foam.
I would try and mash some wheat to avoid the malty beer flavour if this is your concern. Using torrified wheat should allow you to extract the proteins you'd want for head retention, while avoiding the beer flavour. I often add 5% torrified wheat to get a nice strong head, but adding more than 15% and it is likely you will have difficulty clearing your final drink.
Another think that can destroy head formation, even if you have included some wheat or barley malts, is the extraction of fatty acids into the must/wort, minimizing the extraction of these into your solution. In mashes, minimise stirring etc.