This is what I love to do the most.  I have designed high speed video tube cathode drivers, data converters, sinusoidal LED drivers that run at tens of Megahertz, modulators, electrometers that read 40mV signals from electrochemical cells with 10MW output impedance, power supplies and many other circuits.  I enjoy transistor level design, though I am comfortable with everything from tubes to MEMS accelerometers to S-D data converters.  Design for battery power has been a specialty for the last decade.  

My real love and the focus of my spare time is circuits for music.  My music reproduction system features preamps and amplifiers whose genesis was from my home electronics bench.  Most of the instruments I play are either built in these same lab or have been modified there.

Circuit design too can be as simple as a sketch (though my clients will get a pretty CAD diagram instead of the traditional napkin) and as complex as a completed circuit with a complete BOM, theory of operation, noise analysis and layout recommendation.

I am a conservative designer.  I use a modified set of RAC derating suggestions.  If you have in house derating guidelines, I will be happy to use those.  

Please send me a design challenge.  I would be happy to see what I can do for you.