http://i64.tinypic.com/23k3fiu.jpgSomeday soon, crypto-enthusiasts think big financial firms will buy and sell bitcoin like any other asset: stocks, bonds, gold, whatever. But trading on this scale involves volumes and scrutiny that the most popular cryptoasset exchanges today may not be prepared to handle. Although they got in on the action early, these exchanges face costly technology upgrades or ugly meltdowns as activity increases and major exchange operators muscle in on the market.