We actually have a hack that would sort of work for this, namely
having two graphs, one of which auto-copies its data to the other,
like
bmndr.com/d/meta and bmndr.com/d/metahist
But we’re phasing that out. (We have a better way to do it in the
above case of a historical version of a graph. Cf http://beeminder.uservoice.com/forums/3011-general/suggestions/2281054-let-me-see-my-original-graph-even-after-i-reset )
For the case of sleeping neither too much or too little, I’m inclined
to wait to be sure that there’s anyone who really needs to beemind
both limits simultaneously. My hunch is that everyone either has a
problem with one or the other. I mean in terms of actual akrasia,
anyway. Like you can have beeminder force you to sleep enough and then
just start setting an alarm if you get above your road. So beeminder
is still providing guidance on both limits, just that only one limit
has teeth.
Or maybe you want to force yourself to get to bed by a certain time,
and also not sleep in too late. But then just tracking hours of sleep
doesn’t suffice — you really have to track both bed time and wake
time separately since it’s fundamentally two different variables
you’re minding.