Heward's bedroll allows you to sleep in it for one hour to get the full benefits of 8 hours of rest. They're only 3,000 GP, if you got 2, would that allow you to have a pair of 12 hour shifts each day, starting each shift with an hour of rest, and an hour of spell preparation? It wouldn't let you use limited use per day abilities more times (I think? see below), and spell slots used in the last 8 hours can't be recovered, but for the price, it still seems like a decent option. But does it work? The problem is that a wizard's spells are described as a daily allotment.
Though come to think, on another tangent, are there any rules that say when you recover abilities that have limited daily uses? If you use smites, rages, etc right before bed, then wake up and use them, you're theoretically using more than what you get in a day in a 24 hour period, which in normal circumstances is no big deal, but with the proposed use of dual bedrolls, it makes me curious if there are rules that say what you actually recover when you rest for 8 hours somewhere.
Heward's Fortifying Bedroll
Less well known than Heward's other great
creation but still a boon to adventurers everywhere,
this bedroll grants the benefit a full
night's sleep in a fraction of the time.
Description: This item appears to
be a normal, if well made, bedroll. The
cushioning is thick, the stitching
skilled. It is made of dark green cloth
with a dull yellow interior. It smells
faintly comforting, a mix of burning
firewood and goose down.
Activation: To activate the magic of
the bedroll, you need merely climb into it
(a move action) and spend 1 uninterrupted
hour resting. Each bedroll functions once
per day.
Effect: Heward's fortifying bedroll grants you
the benefits of a full 8 hours of rest—including
the elimination of fatigue or exhaustion, natural
healing, and the ability to prepare or ready arcane spells—
over the course of a single hour. Spells cast within the last 8
hours still count against your daily limit as normal.