Stateful Ethernet Bridging and it's effect on overall Internet topology.

I have a question and would like all of your opinions on this matter, as I research heavily into stateful ethernet bridging, packet mangling and their advantages and disadvantages to local and wide area network topologies.

Deployed in large volumes, what negative effects, if any, would ethernet and fiber bridges have on the Internet as a whole.

Lets say I was to build a bridge designed to intercept and manipulate traffic coming in from an outside network into my 'colo site' to do traffic shaping, packet filtering, and ethernet frames manipulation. And I deployed 100s of these into the facility as a means to control overall traffic. Would these transparent bridges be detrimental in any way to the rest of the internet. I understand that since they are re-transmitting data that the possibility of their MAC addresses popping up every time a machine behind it pops up could be an issue when doing network monitoring. But I'd just like to know what everyone thinks about such products.

(Excuse me if my statements seem a little incoherent, I just woke up)