I have several 1.5MBps DSL lines that I'd like to load share. Now hypothetically, can't i just plug all those modems into a switch and then switch into my server/router then the server/router goes into the internal switch. So hypothetically shouldn't it work?

Even if it doesn't load share, won't they all sorta share?

I know it would work if I had a 4-port Cisco router but I can't get one of those just yet.

perhaps. ;)

By "load share" do you mean:

A) Whenever a connection is made, it is split evenly across lines in a "load balancing" function

or

B) Whenever a connection is made, it picks the "least trafficked" line and then travels over it.

For A -> You need software to do it
For B -> You need to setup your switch / router to do it.