If you do end up going the two thermostat route, try buying a model that has
a removable body. Program the two bodies differently and plug in the one for
the week you want.

For example, I have a Honeywell Chronotherm. I can detach the body "for ease
of programming" as it says in the manual.

"Mike Rocket J. Squirrel Elliott"
et wrote in message
...
As a dad who has 50% custody of his two kids -- one week on, one week
off -- I find myself wishing someone made a programmable thermostat that
could preheat the house at 5:30 am during the weekday mornings I get up
early so I can drive the kids to school; yet was polite enough to preheat
an hour later on the weeks I don't have the kids. I get to sleep in longer
those weeks. Every thermostat I've looked at so far has a 7-day program. I
asked the kid at Home Depot about it and he went to ask the manager and
I've not seen him since.

--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westphalia: "Mellow Yellow (The Electrical Banana)"
KG6RCR