[SDPhantom]

I put together some code to do exactly what was described. It only operates on /say and it will attempt to use the emote slash command if it finds one that matches, otherwise, it'll send the emote out through the emote channel. Theoreticly, the slash command emotes support a target argument that lets you specify what UnitID to target. This option has been added in to this code as well.

local Send=SendChatMessage;
local pieces={};
function SendChatMessage(msg,chan,...)
    chan=chan:upper();--    Convert to make checks easier (channel is case-insensitive)
    if chan=="SAY" then
--      Clear our piece table
        table.wipe(pieces);
 
--      Remove empty emotes and strip all spaces around "*" (try to replace empty emotes with a single space)
        msg=strtrim(msg):gsub("%s*%*%s*%*%s*"," "):gsub("%s*%*%s*","%*");
 
--      Split string (strsplit() isn't working the way we need it to)
        for i in msg:gmatch("[^%*]+") do pieces[#pieces+1]=i; end
        if msg:sub(1,1)=="*" then table.insert(pieces,1,""); end
 
--      Iterate through pieces
        for i,j in ipairs(pieces) do
            if #j>0 then--  Don't do anything if string is empty
                if i%2>0 then-- Evaluates to 1 if say, 0 if emote
                    Send(j,chan);
                else
--                  Try to separate command and args
                    local cmd,arg=j:match("(%S+) (.+)");
                    if not cmd then cmd=j; end
 
--                  This is tricky, we need to check if the emote slash command exists
                    local token;
                    local tokencheck,tokenid=EMOTE1_TOKEN,1;
                    while tokencheck do
                        local cmdcheck,cmdid=_G["EMOTE"..tokenid.."_CMD1"],1;
                        while cmdcheck do
                            local slashcmd=cmdcheck:sub(2):lower();--   Skip the slash for the emote command
                            if slashcmd==cmd:lower() then-- Command matches, token found
                                token=tokencheck;
                                break;
                            end
 
--                          Increment command
                            cmdcheck,cmdid=_G["EMOTE"..tokenid.."_CMD"..(cmdid+1)],cmdid+1;
                        end
 
--                      Break if token found
                        if token then break; end
 
--                      Increment token
                        tokencheck,tokenid=_G["EMOTE"..(tokenid+1).."_TOKEN"],tokenid+1;
                    end
 
                    if token then
                        DoEmote(token,arg);--   Performs the same emote operation as supported by chat
                    else
                        Send(j,"EMOTE");
                    end
                end
            end
        end
    else
        Send(msg,chan,...);
    end
end