I have been asked to investigate how we can re-write our Scope of Registration so that we comply with the QS requirements for those customers which require QS, but follow only our internal requirements for other customers, unless the customer has their own specific requirements. It's not really a product line differentiation, just different part numbers that are involved.

This approach is meant to give Engineering more latitude in developing new products and getting them to market faster. Our current scope is pretty generic: The design and manufacture of widgets in accordance with the QS 9000 Quality System standard".

Any suggestions on useful wording?

Refer to the QSR appendix I para 19.
Just my opinion based on a previous experience;
If the products are completely different from each other it is a fairly simple matter to exclude one from your scope. If, however, the products are similar then you may have to identify the product you want
removed from your scope with the following "Not Mfg IAW QS9000" or similar phrase.
Example: we mfg auto filters and fittings.
For our QS9000 scope we include filters only.

In our filter line we mfg OE and aftermkt filters in the same plant.
We could not exclude aftermkt because of the similarity, unless we stated on the filter package that the product was "not mfg iaw QS9000"

You may want to pose your question to the IASG for review and clarification.