DUBAI, May 20 (Reuters) - Saudi Arabia's Dar Al Arkan Real Estate Development Co plans to price a benchmark-sized, dollar-de**minated sukuk of five years duration this week, a document from lead arrangers said. Initial price thoughts for the sukuk are at the high 6 percent range, the document said. benchmark size traditionally means around $300 million for issuers classified as high-yield - meaning they pay a higher interest rate because of their low credit rating. ...