Homebrew PCBs

>I was of the impression from earlier posts in this thread that the 
>stuff you were talking about was lead-free

You can get lead-free plumber's solder paste. You can also get it with 
non-acidic flux. Just buy the one you want.

>Seems to me to be a whole lot easier to use than the stuff I've seen 
>talked about in the context of surface-mount, where it has a limited 
>lifespan, requires refrigeration (!)

I've been using the same jar for about two years, just add water if you 
inadvertently leave the jar open and it dries out. Also, you'll be 
surprised how little is required per board.