In the [KeyMaps] section of eqclient.ini add a line for this if you haven't already. You can bind it to any key you wish. I use y because it's close to r which is the default binding for reply. For some reason it has no default binding *and* it's not even available under keyboard options in the client.

So what does it do?
Press the hotkey and up comes /rtarget <name> and using TAB and shift-TAB cycles through the last people to send you tells. Press BACKSPACE then ENTER to target that person if they are close enough. An example I get a tell for group haste, I hit Y, backspace, enter and ALT-2 to cast the spell. Makes responding to buff requests very fast and easy.

Whats sorta broke?
Two things. It's not listed under options in the client and that darn BACKSPACE you need to press. It put a space after the persons name just like the reply hotkey does which causes the target to fail. Have to delete the space each time before pressing enter.

Anybody else still use this besides me? Would be nice to get it fixed and get more people using it.

Wow, that looks cool. I'll have to try it out.

I go about it a different way.

I have a hotkey with
/rt
/pause 2
/cast 3
/pause 2
/tt Nine incoming!

This targets the last person to send me a tell, casts the buff on them, and sends them a tell to let them know it is on the way - all with the push of a single button. (I keep Protection of Nine in slot 3).

The only time it doesnt work is when someone else sends me a tell faster than I can hit the button.

Can you use this as KEYMAP_DISMOUNT=[button] or is RTARGET some specific command?

What other commands are not listed that work with KEYMAP?

RTarget is a specific command and I don't think there are any other hidden commands like it. This one was advertised in a patch message before the new UI it just seemed to drop off the radar after that.

I use /rt and /tt all the time.

I don't know what the question was.

Was it that you want to bind /rt to a single button "y"?

I don't think he was asking a question. Seemed more to me like he was pointing out that it should be listed in keyboard options as well as pointing out the fact that it doens't quite work right..