If you use a Data report wizard you can use any custom report to show. If you would like to see the 50 "Last seen" assets you could use this custom report to retrieve the data in the Data report wizard:
Select Top 50 tblAssets.AssetID,
tblAssets.AssetName,
tblAssets.Lastseen,
tsysAssetTypes.AssetTypeIcon16 As icon
From tblAssets
Inner Join tsysAssetTypes On tblAssets.Assettype = tsysAssetTypes.AssetType
Order By tblAssets.Lastseen Desc
