""but perhaps its low-end columbus (if such a thing exists....SLX?""

SLX was top of the line...not low-end. Most likely its made of 'Tretubi' (3-tubes) Columbus Aelle...but check the seatpost diameter... if it's 27.0mm then it's probably Columbus Aelle or possibly Cromor. 27.2mm would indicate Columbus SL or SLX.