Hi zmcginn (and others).  Funny that you should ask.  I have been working on a white painted Cecilio electric violin to replace the ebony pegs, tailpiece and chin rest with boxwood, and replacing the maple bridge with ebony.  No idea how it will sound but it should look interesting.  

On your immediate project, I would leave the ebony pegs alone if they currently work.  To replace them, you would need a peg reamer (about $15) and perhaps a peg shaver (about $50 and up), plus a set of new pegs (about $10).  For that kind of money, you could buy a set of Knilling Perfection Pegs (about $60 for the pegs and another $15 for the peg reamer).  A major advantage afforded by the Perfection pegs is that they have 4:1 planetary gears that allow you to eliminate the fine tuners on the tail piece.  This increases the after length of the strings and greatly reduces the weight of the tail piece.  You may want to further experiment by using either a harp shaped tail piece or utilize a 3/4 sized tail piece on a 4/4 violin (to further reduce tail piece weight).

I have used rosewood, maple and boxwood violin accessories (and there are others).  The density of the wood decreases in order, and violin brightness tends to go up as density goes down.  I am experimenting with the use of roasted maple tail pieces (see separate thread on how to do this) and they are my current favorite.

Fortunately (except for pegs as noted above), making the sort of changes you are suggesting can be done very inexpensively if you are willing to waite several weeks for shipments from india and china.  And you can always easily go back to the original accessories (again, except for pegs).  The biggest change you will experience is likely to come from string and bow changes.

I hope that the above gave you a few ideas.