Are there any credible arguments that Jesus may have been gay or tending homosexual? There are a lot of claims that famous figures in history were gay. Peter Tatchell speculates that Jesus could have been. His claim, however, is based on a dubious manuscript.

Have any well-established, credible scholars (historians, psychologists, etc.) claimed in a scholarly setting that, based on the contents of widely accepted historical documents, there is some indication, beyond that of mere speculation, that Jesus engaged in homosexual behavior?

If not, please explain why similar claims are not generally accepted in scholarly settings.
From canonical Scripture alone, I don't think that argument could be made.  

The mosaic law clearly forbids homosexuality in Leviticus 18:22, making it a sin in God's eyes.  If Jeus came, and fulfilled the law, which he said he did, in Matthew 5:17-18, then that would have to mean that he followed the entirety of the law to the letter, including the commandments forbidding homosexuality.  

If New Testament writings are to be taken as truth then, for Jesus to have been perfect (Hebrews 4:15) and thus the only acceptable sacrifice for sin (1 Peter 1:19), he could not have been gay.

If Jesus was gay, then according to Scripture, the entirety of the Gospel would cave in on itself.  Jesus would have been guilty of transgressing the mosaic law, and therefore, owing death as the penalty for his own sin. (Romans 6:23). If he was gay, then, the death he died would have been bearing the weight of his own sin, and the entirety of the Christian worldview would come crashing to the ground.

In short, Christianity depends on Jesus not being gay.

That said, there's nothing that would have prevented the temptation to sin, indeed, Scripture says he was tempted, but he could not have followed through with it and simultaneously maintain the innocence he would have needed to endure the cross, carrying the sins of the world on his back.

Gay Jesus, then, by definition, cannot coexist with Christianity.