I guessed already on this: Stan Pike, and it's all I've got for those initials. These are better and more complete shots of the frame than before...the seat cluster is sort of a variation of the "Victor" style that the Raleigh Pro popularised, but did not invent, there were many others who tried a hand at that style, and Brampton was given the credit for at least naming it. Looks like a very nice frame, with a nod (and wink) to Cinelli.
edit: I should clarify that the B-V or Victor style of fastback is generally meant to describe one with a small "plate" or reinforcing lug-extension on the backside of the seat-tube, which this "SP" frame does not have.
Last edited by unworthy1; 12-15-08 at 07:06 AM.