I don't think you can use a cross tab and get the result you want.
Crosstab cell formulas are summary functions and there is no Concatenate summary function for strings.
You could do this with a regular report and formulas
In the report header add a formula
WhilePrintingRecords;
Global StringVar WorkCodeList;
Global StringVar LevelList;
Global StringVar SignatureList;
Global StringVar DateOrderedList;
""
Add a group on the device type
Delete the group header field from the group header
Add a formula to the group header to clear the lists
WhilePrintingRecords;
Global StringVar WorkCodeList;
Global StringVar LevelList;
Global StringVar SignatureList;
Global StringVar DateOrderedList;
WorkCodeList := "";
LevelList := "";
SignatureList := "";
DateOrderedList := "";
""
In the detail section add a formula
WhilePrintingRecords;
Global StringVar WorkCodeList;
Global StringVar LevelList;
Global StringVar SignatureList;
Global StringVar DateOrderedList;
WorkCodeList := WorkCodeList & ", " & {WorkCodeField};
LevelList := LevelList & ", " & ToText({LevelListField},0);
SignatureList := SignatureList & ", " & {SignatureField};
DateOrderedList := DateOrderedList & ", " & ToText({DateField},"dd-MMM-yyyy");
""
In the group footer use formulas to display the lists
WhilePrintingRecords;
Global StringVar WorkCodeList;
WorkCodeList
Similarly for each list
mlmcc