[R] persp or wireframe 3D plot: how can I independently adjust linewidth of the 'surface' and framebox?

[Matthew Sundling]

It is a trivial matter to adjust the linewidth of the axes and plot  
line in a 2D plot:

x <- 1:10;
y <- 1:10;
par(lwd=2); # axis (and others) linewidth
plot(x,y,"l",lwd=6); # plot linewidth

Is there anything comparable to this for persp or wireframe?  I've  
tried a number of ways, and the framebox/axes seem to be linked to  
the linewidth used in generating the 'wires' of a persp or wireframe  
3D plot.

Also, how can I adjust the font size used in a persp/wireframe?   
Again, axis labels font size don't seem to respond to par(cex.lab=3).

Thanks for the advice,
Matt