Julian

A Textual Commentary on the Greek New Testament, Second Edition, by Bruce Metzger:

Matthew 19.24κάμηλον {A}
Instead of κάμηλον, a few of the later Greek manuscripts read κάμιλον, meaning "a rope, ship's cable." The two Greek words had come to be pronounced alike.

Rope makes far more sense than the, rather silly, text that we are familiar with. I suspect this is the reason why 'camel' is used rather than 'heavy rope.' It is also worth noting that, since the two words were pronounced similarly, confusing could easily spread since many MSS were produced, not by looking at another exemplar, but by copying from dictation.

The word is καμιλος rather than καμηλος in the following manner:
Mark 10:25 -> f13 28 579 l⁵¹⁴
Luke 18:25 -> f13 180 579 1010 1424 l⁶⁸ l¹⁸⁴ l²¹¹ l⁵¹⁴ l⁵²⁴ l⁵⁴⁷ l⁶⁷³ l⁸⁵⁸ l⁸⁵⁹ l⁸⁶⁶ arm (geo) Cyril
Matthew 19:24 -> 174 579 1424 pc l²¹¹ l⁵²⁴ l⁶⁷³ l⁸⁵⁸ l⁸⁵⁹ l⁸⁶⁶ arm Cyril

For what it's worth..

Julian