I don't understand the argument some people are making that the block size limit is OK because the main chain will only be used for relatively rare high-value transactions while new blockchains will arise to serve the masses. Why would Bitcoins on the main blockchain hold their value if new blockchains are popping up left and right? A few die-hard curmudgeons who don't want to change the rules isn't enough to keep the market price propped up.
Well it depends on which "smaller chain" people give their blessing to. In the alt-coin world a lot of chains have come and go- without affecting Bitcoin in anyway.
There actually already is another chain that could be perfect for running as a parallel chain- Terracoin. It's been around a few months and is pretty much a straight copy of bitcoin, with shorter block times (2 minutes), faster diff retarget, lower reward that halves every 4 years (20TRC per block). It's updated by adding the new patches for bitcoin, so it keeps the same consistency with bitcoin as well in terms of security and reliability. The address format is even the same- so there is no need to migrate addresses, your Private key for bitcoin yields the same private key for Terracoin. Although at first some people thought this would lead to confusion, the result has been the opposite. One Public key works for both TRC and BTC, making it very convenient.
The chain is young enough that an increased block size could probably be implemented without much trouble, or so many users to disturb. There is even talk about having it merge-mined to boost its security.
Currently it's traded at Vircurex, Bitparking and Zaptos exchanges. There are several Satoshi Dice like sites, and even an 'instawallet' that is in beta development. It has it's own forums as well:
www.terracointalk.org (because the alt-forum is a bit of a cesspool).
Perhaps terracoin would be fertile soil to test some of these ideas? The user base is very open to testing new ideas.