ksisler

Given the spec of 1/10" gap diameter for the lug to the tube. That might be a bit tight - lets see what others think, but for now, lets use it and the URL for aircraft spruce offered by EpicBike101 to see what off the shelf CroMo tubing might be close to the need for lug making with the OP's current tubeset;

1.125 (1 1/8") your seat tube
-- Needs lug ID=1.225" for 1/10" gap as stated
-- 1 3/8" 0.058" wall with 1.259 ID might work
-- 1 3/8" 0.065 wall with 1.245" ID might also
-- $4.55/ft for either

1.248 (1 1/4") your top tube
-- Needs lug ID=1.35" for 1/10" gap as stated
-- 1 1/2" 0.083 wall with 1.334" ID might work
-- 1 1/2" 0.065 wall with 1.370" ID might also
-- $4.95/ft for either

1.49 (1 1/2") your down tube
-- Needs lug ID=1.60" for 1/10" gap as stated
-- 1 3/4" 0.065' wall with 1.62" ID might work
-- $8/ft

Hope that helps
ksisler