I understand what you want but the issue is not enough height using a hand held on either band and location varies. I doubt another antenna will solve your problem at the same height. Locations inside buildings will still present a problem. About the only improvement I could think of is building a custom antenna with short radials and a longer whip in order to get a match to the radio or a short dual band mobile that still needs a ground plane to complete it, electrically. There is no magic in antennas as they all have to comply with the same requirements, in some way.