There is no limit on BLOB/CLOB/SQLXML types. Which version of Teiid? How are you building your blob? is it serializable?
The length limit is effectively 2^31-1 (the max signed 32 bit int). For blobs/sqlxml length is the byte length and for clobs is the character length. In any case the metadata here should not be causing the exception.
As for the exception if you are on 8.3, you may be hitting https://issues.jboss.org/browse/TEIID-2505 you should try using the 8.4 client driver.