Ok, so I did some thinking about this and here are my ideas on it. For the bottom end, I am assuming that what is already there was built by you and is going to stay there? If that is the case, I would stick wit,h what you already have, but between the tubes plate it out with flat metal, possibly with round holes cut into it, or if you have the ability to do it, it would be even cooler to punch the holes out. So the bottom half would be similar to the hybrid bumper found on this page:
http://www.allprooffroad.com/05tacomatrailarmor/05tacomafrontbumper . For the top half of the bumper I would do something similar to the grill gaurd found on the "full fender coverage style" (the one on the yellow 4wheel off-road truck) found on this page:
http://www.offroaddesign.com/catalog/GMfrontbumper.htm . Basically the top half of that bumper would be tied into your current top tube. Just pick a good line for the center portion of the bumper that flows well with the grill, headlights, winch, and any accessory lights the owner may want to add. Otherwose it looks like you have a pretty good start on things, but my only concern is protection for the front-bottom of the front fender. At least with my driving style that would be a good place to get the sheetmetal caught on stuff...which is why I dont run front fenders lol. Maybe just add a flat plate with some reinforcements behind it to the edges of the bumper. If done right it would tie very well into the rest of the bumper, assuming that you do the hybrid type design I suggested. Hopefully that all made sense to you and you can use at least some of those ideas.