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Nothing will permanently stick to it.
This leaves the glue gun approach. I've seen some good results on forums of drilling a support hole into each tread area, masking it off and building up the area with the glue from the support hole. Not sure how good it will be or, if they'll be any longevity, but it could be worth a go.
@bluebikerider I don't think Quoc's have a replaceable sole either, but they're far more reasonable in price. The only other office friendly / leather cycling shoes I've seen with replaceable sole/tread bits are the Giro Republic's. However, these wear really quickly. Expect to buy lots of replacements if you walk lots.
Muppetteer-
I've been using Quoc Pham's Fixie's for a couple of years now. They're extremely comfy and nobody's mentioned anything about me wearing them to work. Not SPD but I can live with clips n straps and my B has flat pedals.
I'd like to convert to SPD in summer as I do in winter for my Northwaves. I was hoping the Dromartis would do, but they confirmed my suspicions of the sole when I rang them. Too expensive for a non replaceable sole in my opinion.
bluebikerider
I tried doing the same to a pair of sidi's whilst working at a cobblers, so I had access to everything, unfortunately the plastic sole is hard to get anything to stick to....and the sole is the rigid part of the shoe. Nothing will permanently stick to it.