It's almost working but for some reason can't query SQL Express editions.
Query:
SELECT sys1.Netbios_Name0 AS Computer, usr1.Full_User_Name0 AS [user], MAX(CASE sql.PropertyName0 WHEN 'SKUName' THEN sql.PropertyStrValue0 END) AS Edition,
MAX(CASE sql.PropertyName0 WHEN 'VERSION' THEN sql.PropertyStrValue0 END) AS Version, MAX(CASE sql.PropertyName0 WHEN 'SPLEVEL' THEN sql.PropertyNumValue0 END) AS [service Pack],
MAX(CASE sql.PropertyName0 WHEN 'FILEVERSION' THEN sql.PropertyStrValue0 END) AS [CU Version]
FROM dbo.v_R_System AS sys1 LEFT JOIN
dbo.v_R_User AS usr1 ON sys1.User_Name0 = usr1.User_Name0 LEFT JOIN
dbo.v_GS_CUSTOM_SQL12_Property0 AS sql ON sys1.ResourceID = sql.ResourceID LEFT JOIN
dbo.v_GS_CUSTOM_SQL14_Property0 AS sql2 ON sys1.ResourceID = sql2.ResourceID LEFT JOIN
dbo.v_GS_CUSTOM_SQL_Property_2_00 AS sql3 ON sys1.ResourceID = sql3.ResourceID
WHERE (sql.PropertyName0 IN ('SKUNAME', 'SPLevel', 'version', 'fileversion')) OR
(sql2.PropertyName0 IN ('SKUNAME', 'SPLevel', 'version', 'fileversion')) OR
(sql3.PropertyName0 IN ('SKUNAME', 'SPLevel', 'version', 'fileversion'))
GROUP BY sys1.Netbios_Name0, usr1.Full_User_Name0
Class extensions -> http://mnscug.org/blogs/sherry-kissinger/328-installed-sql05-sql08-sql12-sql14-version-information-via-configmgr-hardware-inventory
EDIT: Done, also SQL Express Editions are working