E.g. Is there a converter topology that can take a 12v input and convert it to -12 to +12v output with respect to GND?
For the record I'd really prefer something that doesn't use rare magnetics.
I could do it using a Buck converter and an H-Bridge on the output, but I'd really prefer a minimum cost/parts count solution.
EDIT: Following some great low-power suggestions, I'm actually looking at converting about 100 to 200 watts. It doesn't need isolation or both a positive and negative rail at the same time, just an output that can be adjusted from -12 to +12 volts. Regarding "rare" magnetics, some topologies use tapped inductors that have two windings of different gauges that often need to be customised specifically for each application. I'd prefer a solution that uses normal inductors or something that can be sourced fairly generically.