Ballpark speaking, the RMS current rating is usually 1/5 to 1/100 the pulse rating. If a pulse or dV/dt rating is provided at all.
RMS current limit is thermal, obviously. It can be worse at higher frequencies, due to skin effect and such; CDE 940C caps for example are quite prominent in this way (rated for lots of peak amps, but not very much RMS at 100kHz, and even less at 400kHz -- I know, I've melted them before).
Mind that ceramic chip caps aren't very conductive (they aren't made of Al2O3, or much metal!), so they can't handle the same power level that a chip resistor (typically Al2O3 or metal body) of the same size would.
I have plans to build an induction heater with C0Gs; it'll take about qty 300, wired in parallel. It's a pretty good bit of reactive power handling, though: 100 VA each (30kVA total) isn't bad at all for parts so small!
Tim