R830 Drive capacity upgrade (8 drive to 16 or 24)

This is an odd long shot question , but if I have an R830 with the standard 8 drive frontload hot swap chassis,  Is there a part number or numbers to switch it to a full 24 drive (or even 16 drive) chassis ? or does it mean a complete chassis swap ? 

Basically we have some R830's with additional MD1220 arrays, but things have changed and we don't really need the entire capacity anymore, so condensing them into one 2U space would not only save space in the rack but also some power, and complexity (only have one device to worry about).