Traditionally, many photographers carried 2 film bodies (lighter bodies in those days) usually with different lense lengths and/or film types. Since the advantage of the fx frame is at the wide end and the dx at the long end, how about carrying both bodies and use the fx body with from wide angle work through 200 mm and have the dx available to use to reach out with its 1.5 factor with a 70-200 giving a 2.8 300 mm or with a 1.7 TC giving a f/4.8 510 mm. Does that dx+1.7 TC + 70-200 have any major drawbacks beside carrying the weight of the extra body? My type of shooting doesnt warrant the expense of 400mm or more lense, not to mention the weight. Also, my used d200 body wont bring much,only a fraction of the cost of a 500 mm and keeping it provides a backup body and charged battery. Would this make sense for occasional wildlife shooting or for that extra reach?