Not sure how interesting this is to the folks here but...http://www.esa.int/gsp/ACT/doc/PRO/ACT-RPR-PRO-1107-LS-NTER.pdfhttps://www.google.com/patents/EP2398296A1?cl=en
The european space agency did some work on trying to "supercharge" a nuclear thermal rocket, trying to move beyond a simple inductive heater wrapped around the supersonic portion of the rocket nozzle to heat/accelerate the hydrogen propellant.
The bright spark they had is what they call a turbo-inductor. The basic concept is a turbine direct drive heater, using generator rotor magnets embedded in the tips of a helium loop turbine, which cause ohmic heating in a tungsten heater fin assembly wrapped beyond the turbine tips. They basically use the massive cold sink of LH2 to work with a helium brayton cycle and a nuclear heat source to superheat the hydrogen propellant after it passes through the reactor, allowing the heat to exceed the materials limits of the reactor itself for the downstream subsonic flow.
End up with a nice and compact "electric" heater that is directly driven by the turbine with no intermediary electronics or power conversion systems. Design-wise, they thought they could get the hydrogen propellant hot enough to accidentally melt the tungsten heater section (suggesting the later turbine stages directly inductively heat the hydrogen rather than through the tungsten intermediary heater fins).
I can't imagine many cases where you need to turn mechanical work into heat in a compact manner. The only obvious idea that came to mind was something like NACC-FIRES where you needed to heat air after the nuclear HX before putting into the FIRES container, but a FIRES resistance brick setup sounds much more controllable and cheaper than a turbine mounted heater that you can't easily turn off. I suppose if you wanted to avoid a recuperator or something like that...