If you're not too attached to Gnome, KDE has the ability to bind keys to simulate other keys or even dbus commands in fact.
On other DEs you can still bind your keys to
xvkbd as a way to emulate keys and bind these to your DE "shortcuts" utility. If there is no such utility you can still use
xbindkeys. Here are 2 short tutorials to set those up :
You will find that even with these low level tools, some websites like youtube will not work well with an
<Alt-h> --- LeftArrow keybinding.
I have not found a way to do this at a lower level still. I suspect that it would require a programmable keyboard to achieve what you seek seamlessly. Otherwise it's still very useable and it saves enormous amounts of time, especially if you have such a setup on emacs.