I believe that folder is for crashes in WoW, not disconnections.
This would not be a hard addon to write at all.
Code:
local events = { --[[ your events here ]] }
local f = CreateFrame("Frame", nil, UIParent)
SystemMessageLog = SystemMessageLog or { }
for _,e in pairs(events) do f:RegisterEvent(e) end
f:SetScript("OnEvent", function (_, ...)
SystemMessageLog[time()] = {...}
end)
Should put you on the right track. You'll need to register SystemMessageLog for saves and fix the bugs that are without a doubt there.