A crafting day is 8 hours.
Crafting a magic item is 1000 gp / crafting day.
Increase the DC of the item, you double progress at 1000gp per 4 hours (8 hour crafting day means an effective 2000gp / crafting day)
Using cooperative crafting, you double this and the progress is 1000gp per 2 hours (an effective 4000gp per crafting day.
With the Tireless spell (from Deep Magic or the Zoebeck Gazetteer), you do not fatigue and can craft at "3 times the normal rate". Applied, this is a 24 hour crafting day, which puts the rate of crafting at 12,000gp per crafting day. -- The spell lasts 24 hours, and can be applied to 1 creature per casting.
Would this be a good way to apply the use of the feats with magic item crafting in combination with the Tireless spell?