Combining Internet Sources?

I live in a very rural area and until recently had access only to basic DSL providing download speeds of around 1-1.5 mbps and upload speeds of about .3 to .5 MBPS. A wireless provider moved into the area offering speeds of 3 to 8MBPS and uploads of 1.0 MBPS. So I went for it and signed on. It works pretty well but is occasionally unstable. I get around 3-4 MBPS most of the time.

More recently, my original DSL provider offered "bonded DSL" where two copper phone lines were bonded in a modem and provided 3 to 7 MBPS. Since neither service required a contract I signed up for this one also and figured I'd try them out and see which worked better, then drop one. This one provides 5-7 MBPS most of the time but occasionally bottoms out to near dial up speeds.

I wonder if there is any way to combine these either by hardware or some service to provide faster service and better reliability.

Anyone know of a way to do this? If there was, I'd do it in a heartbeat and keep both services.

 

Thanks I have also heard of a device called a Mushroom Networks "load aggregator" which purports to do the same thing. Said to be VERY expensive, however. Made by a business in San Diego.