What you are describing sound like the Master Light. It is a popular bike which has been in Colnago's lineup for years because its a popular model. It has transformed in its evolution to incorporate a Carbon fork and now carbon rear stays. The downtube and top tubes are fluted.
The paint schemes are an option with Colnagos and no two individual frames are painted exactly alike.
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98 Colnago Altain
08 Pedalforce RS2
00 Specialized Stumpjumper FSR
06 NYCbikes Single Speed (John Deere Special)