If you have an sheathed weapon in a Handy Haversack that you have within reach (IE tied to your belt), can you both reach for said weapon and unsheath it in a single action? Or does drawing a weapon from a Handy Haversack and drawing it from its sheath count as two actions?
Some weapons have to be sheated before being put into a handy haversack or they risk perforating it. You still need to unsheat them after drawing them, unless you have the Quick Draw feat or the Magic Item Compendium weapon crystal that doubles the feat.
Using a club or some other weapon that does not need to be sheated could be a nice alternative.
To retrieve a weapon from a haversack then draw the weapon,
Usually This Takes 2 Move Actions
Heward's handy haversack (DMG 258) (2,500 gp; 5 lbs.) says
Emphasis mine. So even if a creature's strapped the magical backpack to his belt (somehow), it's still a move action to retrieve the weapon from the haversack as removing any item from it is a move action.
Then Things Get Slighty Murky
I'd argue, after retrieving the weapon from the haversack, then the weapon must be drawn, and that there is no distinction between unsheathing a weapon and drawing a weapon--the term drawing a weapon is an abstraction used to indicate what one does to ready one's weapon usable in combat. The Player's Handbook makes this fairly clear:
Thus, once a weapon's been retrieved from the haversack, it's within "easy reach," and can be drawn like any other weapon within easy reach, usually by taking a move action or drawn simultaneously when the creature takes a move action to move up to the creature's Speed. The draw a weapon action must occur even if the weapon's a spear, mace, or sword. Maybe the haversack always spits out the spear at an awkward angle or whatever.
The problem is that when the Player's Handbook says that a weapon's "cost includes miscellaneous gear that goes with the weapon, such as a scabbard for a sword or a quiver for arrows" (PH 114), it doesn't go on to detail which weapons include miscellaneous gear such as an appropriate container, leaving such judgment entirely up to the DM. Should a spear be stored with a leather wrap covering the tip? Probably. But only the DM knows for sure, and only the DM knows if he wants that kind of detail to matter.
Further, while the bag of holding (DMG 248) (2,500+ gp; 15+ lbs.) says that
the haversack doesn't say this. However, the DM could rule that because each pouch is like a bag of holding, the bag's rupture-and-ruin clause applies.