Digital BW, The Print

Good morning,

I just made my first stiched panorama using PSCS Automate>Photomerge
and I just love the result (being an ex-8x20 large format user) but I
was disappointed that it coerced the result file to 8bit. 

Can anyone suggest a high quality stiching program that allows you to
keep 16bit output?

Thanks!

Guy