Ok, now is the answer.
1) I agree that transparent .gifs weren't even planned for this. But in reality, this is really SIMPLE and EFFECTIVE solution, which works the same in MOST browsers. Don't you think we have not tried to use CSS instead of it? Of course, we tried. But nothing funny was there. Orienting mostly on Internet Explorer and Mozilla, maybe little bit Opera, making a layout using transparent .gifs is the only best solution for now, because CSS is looking DIFFERENT.
2) So, miniBB is not for 10 million hits, and we are not propagating it. If you have this amount of hits, you need to buy more serious software. On another hand, even if it could be, you are wrong saying that it will eat your traffic. !pix.gif will be stored in browsers cache, and since it is identical on all pages, will be reloaded rarely.
I still haven't heard exact solution from you. If you offer to change !pix.gif to something, what something?