Dungeons and Dragons 3.5 artificer item creation LV?

Creating magic items has always been a little vague in the rules. (And I can't give you exact page numbers right now, but I believe they are in start of the magic items chapter.)

To start you need the appropriate feat. Every magic item has an associated feat that allows you to make them. Your +5 sword requires 'Craft Arms and Armor', while the +6 Cloak of Charisma requires 'Craft Wondrous Item'.

The next stage depends on what level your DM is going to make you roleplay item creation:

-If your DM requires full roleplay, you will have to gather the ingredients he says and secure a work space.

-If you item creation happens 'off-screen' you can be assumed to be doing this during the breaks.

Most magic items (potions exuded) require material worth 1/2 the items market price. The sword will cost 25,000 gp in materials (plus the base weapon), the cloak 18,000 gp.

Magic items also require XP to craft. (Again excluding potions). The XP cost is the item's market price divided by 25. The sword will cost 2,000 XP to craft, the cloak 1,440 XP.

You must have the ability to cast the spells in the item's requirements. From my reading of the rules you have to have this spell prepared for every day you work on the item, and doing so expends the spell for the day. There are no spell requirements for a straight +5 sword, but a +4 Flaming sword requires flame blade, flame strike, or fireball. The cloak requires eagle’s splendor.

Magic weapons and armor (and some wondrous items, such as Cloaks of Charisma) require that your caster level be three times the enchantment level of the item. You must have a caster level of 15 to make the sword. The cloak does not have a requirement.

It then takes a number of days equal to the market price of the item divided by 1,000 to actually craft the item. (Again, potions are an exception). The sword will take 50 days to make, and the cloak 36. Note that these days do not have to be contiguous, but you can only work on one item at a time and it will cost you 8 hours of work during a day to count as a day of work. You will have to have eagle’s splendor prepared to be able to get a day's work on the cloak.

Artificers (the Eberron base class) bend several of these rules, and outright break one of them. E-mail me if you want specifics, but in general they create magic items based of of UMD check instead of having to prepare a specific spell.