Unlimited power with SRD only materials

[gooddragon1]

Successfully binding an Efreet played to his full power requires more than just the listed stuff. It would be easier just to buy a candle of invocation from your WBL, which is sufficient for that at 5th level.

@Your Wish
Doesn't work, since the XP cost for adding that ability is not defined. While the Solar doesn't have to pay it, it is a cost and must be a discrete number:

You can force the solar to create an item of basically unlimited power for you, that adds all kinds of existing abilities, but you can't force him to create an item with abilities that don't have a defined XP-cost, and there's no RAW that forces the DM to allow the creation of items that aren't pre-designed in sourcebooks.

Through 1 method or another it will work. Either through granting epic spellcasting power by which ad hoc adjustments allow anything and thus my combo works (thus an existing effect) or more broadly by the fact that the words "Create a magic item" do not specify an existing magic item and there is such a thing as the custom magic item creation rules which therefore mean that items and effects not listed may be created. Furthermore, the only requirement a DM could request is an unlimited amount of XP to create the item you request but you may safely ignore all other prerequisites by the wording. You have an unlimited amount of XP to work with as it doesn't require any for the Sp ability. This means that because the only limiting factor is not a limiting factor there are no limiting factors on what you can create by RAW.

A spell-like ability has no verbal, somatic, or material component, nor does it require a focus or have an XP cost.

The ability always lacks an XP cost altogether.

No XP cost, no limit magic item creation rules, and the only limiting factor that the DM can request is XP mean no limits on what you can do RAW.