Get an Edwin Jagger, they have many handle options or you can even purchase a separate handle for it (UFO, Griest Shaving...). Gillette Techs are similar to the HD as well and you can get different handles for that one too. I enjoy the versatility of the 3-piece razors.
If you like the 34c, then try the 38c or 23c. An EJ 89 is a great 3 piece choice that can accomoodate alternate handles.I love my Merkur HD but wish it was a little longer. Does anyone have any suggestions?
Thanks