I did some research on this a few years ago, and I finally came to the conclusion that the evidence is SO thin - and SO equivocal, that you really can't reliably assume that Crusaders wore anything but mail.
There is the so-called
"Charlemagne Chess-set", apparently made in (Norman) Italy at the end of the 11th century which shows warriors in what could be interpreted as lamellar armour.
There IS a picture of King Ninus in a "History of the World" produced (I think) in the Holy Land in the mid 13th century, where the guards are wearing what appears to be scale armour. However, the rest of the illustrations in the same source are apparently of yer standard mail-covered western style knights.
There's also an illustration of the Fall of Jerusalem that shows an interesting mix of Eastern and Western styles of armour.
But in my opinion, we're looking at people copying others' artistic styles, not mixes of armour.
Having said all this, I'd be very happy to revise my opinion on this - if the evidence could be found. I'd also be interested in seeing photos of the carvings mentioned above.
Unfortunately there's the tendency - particularly for people who don't like mail - to jump on the slightest shred of evidence to justify the use of other types of armour in a Crusader context.
Just be aware that the evidence for Crusaders wearing mail is so thin as to be almost non-existent, and to portray one accurately according the best available information you would use mail, not lamellar.