I have cut a water outlet short and then ground a light ring on the snub for hose fitment on a chubby chevy back in the day, (it was a zero dollar budget overhaul..) and it worked fine.. if you have to resort to drastic measures...
Oh good freaking lord do we need to do the electro. Vs mech. water pump thing yet again?
LOL!
I never heard of a short version BBM water pump but that post above is a good idea he beat me to. Milling the pump mounting points could help.
How much room do you need? Can you provide a picture by chance?