%
% /newfont encoding /basefont `encodefont' newfont
% 
% Note that the encoding is actually an array, not the name of an array.

/encodefont {
    findfont dup			% Get the old font dict
    maxlength dict begin		% Make a new one just as big
    {	1 index /FID ne			% Copy everything but FID
	{   def	}
	{   pop pop }
	ifelse
	}
    forall
    /Encoding exch def			% Install the new encoding
    dup	/FontName exch def		% new font dict is still current.
    currentdict definefont		% Create the new font.
    end
} bind def

% Sample use:
% /CourierI ISOLatin1Encoding /Courier encodefont pop