I've been having a look at random maps as well, so far I have a simple program that generates stuff like this http://pastebin.com/66pg2h0X ( || is hedge, ## is road, ** is grass)
it is just for farms at this moment, as those are relatively simple and I still need to flesh out the algorithm a little more and write the xml parser obviously but then atleast for farm I can probably generate a pack of a thousands maps or something like that