replacing a textarea with a same-sized editor

Is there already a way written for this? I've hacked this in by changing fckeditor.js to have the following:

var FCKeditor = function( instanceName, width, height, toolbarSet, value )
{
// Properties
this.InstanceName = instanceName ;
this.SizeSpecified=width||height;
this.Width = width || '100%' ;
this.Height = height || '200' ;
...

and

FCKeditor.prototype.ReplaceTextarea = function()
{
...
if(!this.SizeSpecified){
this.Width=oTextarea.offsetWidth;
this.Height=oTextarea.offsetHeight;
}
oTextarea.style.display = 'none' ;
...