Clasificación de datos para la fuente PIVOT

A menos que me falte algo en su explicación, entonces no necesita AttributeMask . Si los nombres de las columnas finales van a ser solo los nombres de las columnas originales y luego el Kind valores, entonces puede usar:

select *
from
(
    select LotId,
        SomeText,
        col+'_'+Kind col,
        value
    from
    (
        select l.LotId, 
            l.SomeText,
            cast(a.AttributeId as varchar(8)) attributeid,
            cast(a.LotId as varchar(8)) a_LotId,
            a.Val,
            a.Kind
        from @Lot l
        left join @Attribute a
            on l.LotId = a.LotId
    ) src
    cross apply
    (
        values ('attributeid', attributeid),('LotId', a_LotId), ('Value', Val), ('Kind', Kind)
    ) c (col, value)
) d
pivot
(
    max(value)
    for col in (attributeid_Kind1, LotId_Kind1, Value_Kind1, Kind_Kind1,
                attributeid_Kind2, LotId_Kind2, Value_Kind2, Kind_Kind2,
                attributeid_Kind3, LotId_Kind3, Value_Kind3, Kind_Kind3)
) piv;

Consulte SQL Fiddle con demostración . Esto da el resultado:

| LOTID | SOMETEXT | ATTRIBUTEID_KIND1 | LOTID_KIND1 | VALUE_KIND1 | KIND_KIND1 | ATTRIBUTEID_KIND2 | LOTID_KIND2 | VALUE_KIND2 | KIND_KIND2 | ATTRIBUTEID_KIND3 | LOTID_KIND3 | VALUE_KIND3 | KIND_KIND3 |
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|     1 |  WithAll |                 1 |           1 |        Foo1 |      Kind1 |                 2 |           1 |        Foo2 |      Kind2 |                 3 |           1 |        Foo3 |      Kind3 |
|     2 |    Hello |            (null) |      (null) |      (null) |     (null) |                10 |           2 |        Bar2 |      Kind2 |            (null) |      (null) |      (null) |     (null) |
|     3 |    World |            (null) |      (null) |      (null) |     (null) |            (null) |      (null) |      (null) |     (null) |                12 |           3 |        Bar3 |      Kind3 |