Because neither entity names nor bundle machine names are in a database table, there is no official maximum length.
Some entity modules store their bundles in the DB, eg node stores node type with a length of 32, but this is then increased by comment bundles which adds an 11-character prefix.
This leaves contrib modules guessing what to do when they need to store (eg).
I suggest that entity API docs should state a maximum length for entity and bundle name length -- say something like 64 -- so anything wishing to store them knows what size field to define.
PASSED: [[SimpleTest]]: [PHP 5.4 MySQL] 67,042 pass(es). View
FAILED: [[SimpleTest]]: [PHP 5.4 MySQL] Failed to run tests: PHP Fatal error encountered during run_tests.sh. See review log for details.. View