so this isnt your typical car carbon fibre questions.

Ironically i was talking about making a guitar with a guitar maker friend a while back.

If you want a functional guitar, then an electric is the only way as an acoustic guitar you wouldnt get the same sound due to the material being used. Not that it would be impossible to make an acoustic guitar but youd need to design it.

There are carbon acoustic guitars out there: Carbon Guitar

However there shape has been teaked and carefully designed to take account of the different sound properties carbon has.

Luckily you are making an electric....

Made of carbon it will be plenty stiff enough to keep in tune so thats not a worry, and obviously the sound quality has more to do with the quality of the pickups and electronic equipment you fit.

In terms of moulding it, I suspect you dont want to buy an expensive guitar to use as a mould!!

if you could get a CNC plan of it then things are much easier. You could make a plug out of CNC milled foam and work from there, or use the measurements from the CNC plans to hand make the plug from foam.

You will need to consider your design carefully, probably needing several moulds, possibly several part each for the body, neck, fret board and head etc.

When i discussed it with my mate over some beers, we thought youd want a 2 part mould for each large part.  You can join them together by carefully desiging an overlap into the moulds.

eg make the bottom of the soundbox using the foam plug, then once happy, modify the plug to leave you a slight recessed overlap area when you make the soundboard mould so that there is an overlapping join.  Its more important to have a good seamless join on an acoustic than a electric. 

Use a similar technique on the fretboard and head.  Of course you could hand lay around a foam core and later dissolve the foam if you want minimal join lines, however it would need more preparation work to the finished part to get a nice smooth surface finish.

You could copy the idea in the link i posted and keep a hollow fretboard and head.  In theory you could then just have 2 moulds, a top and bottom.

Also consider how you are going to fit the frets, nut, tuning pegs etc.

It is doable though.

You dont need diamond cutting equipment!! You just need carbon shears to cut dry fabric and some tungsten carbide grit tools to do the cutting and filing of the finished parts.