I have not yet added the "type" argument to functions densityMap or contMap; however it is already possible to create a circular densityMap or contMap style tree. Here's how:
Loading required package: phytools
> # simulate tree & data
> # first plot typical contMap & obtain "contMap" object
> XX<-contMap(tree,x) # we don't care about this one
> # now plot with type="fan"
Note: type='fan' is in development. Most options not yet available.
> # finally, add color bar
> # (we have to click where we want this)
> add.color.bar(0.8,cols=XX$cols,title="trait value", lims=range(x),digits=2)
Note that we have to click where we want to put the color bar/legend.