The Koolstops can be bought with the shoes (couple of quid more), or without. (I only realised this weekend just how easy it is to carry spare inserts - they're tiny and weigh f-all.) They're the same shoes as Shimano Dura-ace, and probably many others from my limited experience.
Spa seem to be quite cheap for them at the moment.
I love the Koolstops, but wonder if there is something cheaper I could get for the dry-weather bikes? (that isn't totally rubbish, or eat my rims).