The number of files needed to make it crash is not always the same. Sometimes it crashes when renaming like 6-7 files in a row, othertimes it needs a bit more. It doesn't matter if I right click and then click rename on every file or use the F2 shortcut.
Possibly a duplicate of bug 12264.
Can you reproduce with thunar 1.6.12?
Very likely fixed since then, reopen if not.