Why not make a type of platform where there is an SPD cleat attached and can be fitted with clips and straps which just clips in to the pedal. Just twist if off when using your SPD shoes. Or as an example you could just buy these or find something similar. Amazon.com: Exustar SPD Clipless Pedal Adapter: Sports & Outdoors It won't give you the proper "vintage look" but trying to fark around with clipless shoes/pedals with clips mounted may change you mind very quickly. You could also mount a quick release pedal axle system that would make changing pedals fast and easy. http://www.bing.com/images/search?q=...xles&FORM=IGRE