How to efficiently use 3D via a remote connection?

You could check out VirtualGL together with TurboVNC should provide you with 20fps @ 1280x1024 on 100 Mbit (see wikipedia).

Do note that it might not work with all applications, it depends on how they use OpenGL.

This is an old question but it is still relevant. There is a step by step manual on how to configure and troubleshoot X11 3D rendering of remote application on local hardware: OpenGL hardware acceleration through remote x11 ssh connection

The Chromium B.S.U. game is used in the article as an example. It runs with 5-8 FPS with default software rendering through SSH connection, 30 FPS with indirect hardware rendering and >30 FPS with unencrypted TCP X11 connection. Note that it only works for some applications.

Brief summary of the article

Indirect rendering and TCP connections are disabled in default X11 server configuration. +iglx and -listen tcp parameters enable them. There is also LIBGL_ALWAYS_INDIRECT=1 variable that forces indirect rendering on the X11 client.