In the days when Ergo shifters weren't common, Campag and Shimano made down tube cable guides which fitted the same lugs as down tube shifters. They are still made so you could remove the levers from the clamp and fit these guides.
http://www.campagnolo.com/repository/documenti/en/Spares10-B-010909.pdf (on the bottom left of the very last page)
@yoav started
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In the days when Ergo shifters weren't common, Campag and Shimano made down tube cable guides which fitted the same lugs as down tube shifters. They are still made so you could remove the levers from the clamp and fit these guides.
http://www.campagnolo.com/repository/documenti/en/Spares10-B-010909.pdf
(on the bottom left of the very last page)