Thank you kimo. I had forgotten about 'in' as an SQL operator (i'm a recovering SAS programmer). This makes the code much more clear. Using a new select, then select from.. as you suggest simplifies things as well.
It appears that what I was missing is that the arguments to the arcpy function all have to be within a single quoted string. The following line returns the 14 expected values.
arcpy.SelectLayerByAttribute_management ("view", "NEW_SELECTION", """ "SP10" in ('WS','BS','JP','BF','TL') and "SP11" in ('TA','BP','WB','WE','GA','MM') """)