I'm using MySQL Workbench CE 5.2.30 CE / Rev 6790 . When execute the following statement:
With this setting you will be able to concatenate fields without getting blobs.
I think this applies to versions 5.2.22 and later and is the result of this MySQL bug.
Disclaimer: I don't know what the downside of this setting is - maybe when you are selecting
VARBINARY values you will see it as plain text which may be misleading and/or maybe it will hinder performance if they are large enough?