In this new post to his blog, Rob Allen has posted notes on some of his experience in working with blobs with SQL Server using UTF-8.

This turned out to be easy enough: Use ntext, nvarchar types in the database and add resources.db.params.driver_options.CharacterSet = "UTF-8" to your application.ini

He also includes some code to fix a problem he spotted with storing binary data into a varbinary field giving him an error about string translation. The fix came in the way of replacing the direct file_get_contents assignment to a variable over to a binding method that specified the data type as well.