DonDuckie |
There aren't rules for that specific item, but I would allow it.
The rules do mention adding magic qualities to other (magic) items at a 50% increase in price, so you make a "ring of disable device" added to a (masterwork) skeleton key.
And maybe it should be an enhancement bonus rather than competence.
PrinceDogWaterIII |
RAW, pretty sure you're stuck with a mundane skeleton key. No reason not to just get a magical set of thieves tools and enchant them like a competence bonus item.
First find a magic with a similar price with a similar ability.
Now since your tools are an un-slotted item we go to magic price GUIDELINES. Multiply the cost by two to get your slotless tools that has been enchanted for a +5 bump to Disable Device.