Something of interest here might be centralising services at NAPs. For example, putting a news server at the NAP running Cylone, the NAP purchasing a news only T1 (or whatever) to serve the box, and then participants who would like a news feed getting it directly from this box and paying extra.
Another intersting saving is via proxy neighboring over a local NAP. Rather significant traffic savings have been observed in local NAPs inside Australia by participants neighboring squids. AU being a rather heavy user of caching compared to the US.
Other ideas were tossed around including a central DNS server/cache, gaming servers, etc.. and one peering network inside AU (Ausbone) is doing this.
This was discussed several times in the UK but politics always seemed to prevent setting this sort of thing up at LINX (as far as I could tell). Others probably know more. Certainly the idea seemed very sensible. Manar