You just love making my life difficult don't you?
a) For an extra 4 gp you can add a money belt. Holds 50 coins and raises Pick Pocket DC by +5.
b) Masterwork Bandoleer (holding 6 boomerangs) costs 5 gp to buy. (None masterwork are 5 sp).
In order to add the "re-filling" effect then things get complicated. There are two ways to do this as far as i can see.
1) To have the Bandoleer conjure new (short life-span Boomerangs) each time one is removed.
2) Have the Bandoleer imbue the 'Returning' ability (for 1 round - to keep the cost down) on anything drawn from it, bearing in mind that it is designed to only hold Talenta Boomerang.
I think option 2 is probably the easiest, this way you need
telekinesis rather than
fabricate.Returning is a +1 enhancment
Spell level (telekinesis = 5) x Caster level x 2000 gp (use activated)
Divide by 2 (due to it only working on a specific item)
Divide by 5 (due to it only imbuing enhancement for 1 round)
Just an idea - Not gospel