Spindle moror ideas and thoughs of building a steroid based xcarve

So I have been tossing around the idea of my own version of the xcarve but with alot more beef for milling metal. Construction would be ballscrew bigger steppers steel frame and heavy linear bearings. With all that aside I have been racking my brain trying to find a low speed high torque controllable spindle option in a small package and then I remembered the old wood lathe I fitted with a dc tread mill motor it was 2.5 horse not too bulky and could run well under 1600 rpm with the speed controller from the treadmill and the cost was not too bad. Time for this project is not a issue as I will get what I need here and there when time and money permits. The motor will drive a spindle shaft with a timing belt. construction of the spindle will be large pillow block bearings and a precision machined shaft with a collet done by the local machine shop. So am I crazy or should I do this any input would be appreciated. I am well aware I is not too hard of a task to buy a grizzly or harbour freight bench top mill and convert it But I love making my own tools.