Well, I much prefer a weight belt. But I never put more than 6 to 8 pounds on it, if any at all. With minimal weight, a weight belt sorta disappears. Now, for larger fellas, a weight belt can be problematic. Bigger guys tend to need more weight on the belt and this, coupled with the low "hip to belly ratio", results in a belt that wants to migrate south.
This might be an area where backplates offer a unique advantage. By using a heavy steel plate more of the required total weight can be put on the back as it is taken off the belt. This makes the weight belt more manageable and trim characteristics more favorable. Of course, the advantage of traveling light sorta goes out the window. It certainly is no fun to cart a 12 or 15 pound plate around in your gear bag. As bad as that sounds, it is the total weight of your bag that counts. So if you can manage to keep your gear bag to around 45 pounds or so it would be no big deal.
Nevertheless, a better option for you might be to just bite the bullet and get the weight pockets. The Halcyon jobs come in two sizes, as I recall. I have a pair of the smaller ones and though I don't normally use them, I do sometimes put them on one of my rigs that I'm lending out for others to try. They seem to work pretty well as most of the folks that I lend it to normally use weight integrated BCs. They like that particular similarity. They are pretty nice in that they attach to the plate and are kept nicely towards the rear of the waist belt. They also make dialing in your weights pretty easy...it's very easy to add or remove the weights in each pocket. Also, another advantage is that they do afford dropping weights in increments should the need arise. (Although that is another topic in and of itself.)
I suppose another option would be to use a weight harness. They have suspenders that keep the weight belt from sagging. I have no experience with these but there are a lot of guys that really like 'em.