>> Does anybody use these?  Find them at Digikey, or Mouser, or etc?

>Such as the Raychem/tyco "Polyswitch" series, available at digikey/etc.
>
>I have some from dumpster diving.  They seem a bit slow to me, taking a
>couple seconds to open (that may be something you can select, though.)

Yeah, they are really designed as a safety device to handle long term
overloads, rather than used like a normal fuse. Not sure what the minimum
current rating is, but I doubt that they will really suit the OP desires.
There are surface mount ones that might get close though.

The other trick to them is that they are designed to work close to max
current rating, but if you try and grossly exceed that, then they will act
rapidly as they then heat up fast. Makes them good for protecting
transformaers in power supplies from short circuit outputs, instead of using
fuses.

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