bykerouac, very nice bike!

What is the motivation for the corks? If it is to provide resistance to the handle clamp you may want to look at these plugs http://www.ergon-bike.com/us/en/product/ls100

I noticed that you are using regular seat clamps. Did not know that they fit. I may do the same if it preserves better the pitch adjustment when removed.

If you want to go all the way with brake mods, here is an interesting example with V brakes. Am not sure how it was done. Possibly some brazing.

http://www.flickr.com/photos/brompfi...n/photostream/