When I visited Japan many years ago I saw some stunning bonsai, many over 100 years old handed down from generation to generation. Unlike you I've never had much luck with bonsai but recently I decided to try again with Ficus Microcarpa. While not a bonsai in the traditional sense they look good and so far I've managed to keep them alive for a few months, a major success for me. Maybe a Chinese or Japanese elm is in my future.