A rack like the Surly seems to me like overkill for the load you expect to carry. It weighs over 2 lb 12 oz, which seems like a lot to support a 15 pound load. It is also about $140-150.

A few things to consider on the topic of front platform racks...
With smaller frame sizes, if you use a handlebar bag there isn't much room to put anything on the platform. That said, I have used a little platform rack to hold my handlebar bag. It actually weighed less that the bag weighed in its intended configuration, because the bracket and stiffeners that I removed weighed more than the 12 oz rack I used instead.

The little rack is sold under the Nashbar and Sunlite brands and price is about $13 or sometimes even lower. I own several of these racks on different bikes and they have held up well. I typically do not put more than a few pounds on them though. I definitely wouldn't try to hang panniers on them. If you need panniers and a platform, the little rack can be used with a low rider rack.