The easiest to pull off will be whatever components you can find the cheapest!
Even if it already has "long reach" calipers on it, some manufacturers have made SUPER long reach calipers. Keep an eye on eBay. I've seen calipers from Tektro that have reach up to 78mm. Here's an eBay auction:
http://cgi.ebay.com/TEKTRO-LONG-LONG...em230041499937