Wireless Solar Volatiles Spiral Mining System
It might not be very exotic in appearance, but this is a utilitarian machine.
The upported hi efficency GaAs solar panel farm generates about 10MWe.  Power is beamed to mobile tower-compressors-cooling unit-storage tanks assembly that is moved after each 1.13 km diameter (one square kilometer) circular area is complete.  Entire area is about 7 km square or 49 square km, but only 28 circles are mined out, so a rectilinear mining pattern might be more efficient.   If one sq. km mined per year to depth of 3 meters, about 6 million tons/yr., then about 80 tons carbon, 200 tons hydrogen, 20 tons helium4, 16.5 tons nitrogen, are obtained, based on figures by Dr. Kulcinski.  Over 28 years, 2240 tons of carbon, 5600 tons of hydrogen, 560 tons of helium and 460 tons of nitrogen are mined.  Numerous mining systems would be at work on the Moon to get volatiles worth billions of dollars due to the cost of space transportation.
This page was inspired by work done at the University of Wisconsin.  See: http://fti.neep.wisc.edu/pdf/fdm1304.pdf

During discussions with associates objections were raised about the fragility of heat pipes and the high power of over 10 MWt. 

Perhaps more power is required.  If six million tons of regolith is mined per year and 10% of the smallest fines extracted and heated to 600 C., then at 840 j/ kg. K and 151,000 kg. per hour of fines, 21.23 MWhrs of energy is needed, or the equivalent of burning two pounds of coal per second.  That doesn't seem like too much.  If the fines are heated to 600 C. and dumped, heat energy will be wasted.  The University of Wisconsin researchers used waste heat from spent fines to preheat incoming fines.  This isn't perpetual motion but simply transferring heat from one mass to another to reduce total heating requirments.  Very little heat is conducted away by the evaporating volatiles as their mass is so small.  Since significant amounts of heat can be recycled less than 20 MW of power might be used.  However, I have not accounted for inefficiency of electrical systems and microwave heaters. 

In addition, it is not necessary to heat the particles completely through, but only their surfaces that the volatiles adhere to, so much less energy is required than one would think based on simple calculations using mass throughput and specific heat cap. of basalt rock (1).  U of Wisc researchers calculate 12.3 MW to heat 45% of the fines, about as much energy as is released by burning one pound of coal per second.  Since the onboard furnace will reject most of that heat, there is no danger of it overheating.  Still, given to low heat conductivity of regolith and the fragility of heat pipes, it's hard to imagine anything more practical than microwave heating.
Smaller mining machines will be used initially to harvest enough iron fines to make steel with upported carbon (a few tons, enough for several hundred tons of steel).  Some titanium will be produced too.  Larger mining machines will be constructed on the Moon as industry grows from a small but substantial "seed."  The challenge is to make maximum use of lunar materials and simplified designs.
A simpler alternative to the "ditch witch" excavating system.
1) Lunar Material Resources: An Overview*
James L. Carter

http://www.nss.org/settlement/nasa/spaceresvol3/lumareov1l.htm
Another regolith miner image that uses hi speed archimedes screws sort of like some snow blowers to mine and transport Moon dust to onboard electric furnace energized by recieved microwaves.  Uses standard chasiss and wheels. 
ABOVE:  Graphite resistors heat surfaces of moondust particles falling thru furnace that will consist of hundreds of pipes with graphite resistor heating elements.  Though I said above that conduction heating was useless. we really only have to heat the surfaces of the particles that the volatiles adhere too.  Residual heat and prewarming system recovers heat with a system of gas filled pipes. Perhaps some microwaves will also be emenated from metal pipes with heating elements within for extra heating power. 
Large stationary solar powerplant transmits energy by microwave beam to mobile tower and cooling units with storage tanks.  Mobile tower remains stationary while tethered mining tractor extracts volatiles that are piped thru hoses to the tower unit where gases are compressed and liquefied or stored as hydrides.  When the tower unit's tanks fill up another robot rolls out and exchanges storage tank modules.  When a circle is mined out the whole system, mining tractor and tower unit, move to new territory.  The mining tractor is much lighter than the tower unit with its compressors, cooling units and storage tanks, so energy is saved by this division.