Cheesey Spell Clock Request

[unseenmage]

It was pointed out to me recently that the Spell Clock (http://www.wizards.com/default.asp?x=dnd/cw/20070312a) has it's spell placed in it at creation, not later on as I'd originally thought.

Which brought the question to my mind, how much more would/should it cost to make a Spell Clock whose spell can be changed to a new spell by casting a new spell into the clock after stopping it?
How much more for a Magic Trap whose spell can be changed to a new spell after disarming it?

Additionally, how much more should a Spell Clock cost that casts multiple spells?

[Slipperychicken]

Additionally, how much more should a Spell Clock cost that casts multiple spells?

Using the magic item creation guideliness..


Multiple Similar Abilities
For items with multiple similar abilities that don’t take up space on a character’s body use the following formula: Calculate the price of the single most costly ability, then add 75% of the value of the next most costly ability, plus one-half the value of any other abilities.

Calculate the value of a spellclock for each spell, then modify them accordingly.

Bear in mind this will quickly bring the item's value above the 200k limit, after which it becomes an Epic item and you need the Epic version of the craft feat to make it.


In general, an item with even one of these characteristics is an epic magic item.

Grants a bonus on attacks or damage greater than +5.
Grants an enhancement bonus to armor higher than +5.
Has a special ability with a market price modifier greater than +5.
Grants an armor bonus of greater than +10 (not including magic armor’s enhancement bonus).
Grants a natural armor, deflection, or resistance bonus greater than +5.
Grants an enhancement bonus to an ability score greater than +6.
Grants an enhancement bonus on a skill check greater than +30.
Mimics a spell of an effective level higher than 9th.
Has a caster level above 20th.
Has a market price above 200,000 gp, not including material costs for armor or weapons, material component- or experience point-based costs, or additional value for intelligent items.


Prerequisites
In addition to the materials and tools required for nonepic magic items, any epic magic item requires at least two item creation feats: the epic and nonepic version.