If you have access to a welder or know someone who can weld, weld a nut onto the inside of the dropout and make your own built in chain tensioner. It's basically the same as the DECO, St Martin, Jungle Rider, etc. dropouts and a lot of people here in Japan, including myself, do this to our own frames that didn't have them. Check the URL below for a picture of it.http://www.flickr.com/photos/decobmx/5620082587/#
just remember to remove paint from area to be welded.the nuts you purchases also can't be the type that has zinc or any other type of plating/coating on them. your intial post suggested a sprocket/ chainstay length/ chain length inccompatibility + wheelbase length issue. welding nuts to get chain tensioners are great, but doesn't solve your need to slammed the wheels as far forwards as possible.
And I totally can not understand how anyone who has ridden flatland can design a dropout like this. Completely bullsh*t without any advantage except saving 3,62 g...