I'd look on craig's list for another tank, they are cheap especially if they were fish tanks that leaked or check petco for $1 gal sales if you have one in your area. you can use plexiglass as a divider (though the smaller the space the harder it is to control the temp/create an adequate thermocline), Lowes in our area will cut it to size or if you are handy with a jigsaw and grinder you can cut it yourself. it's easy to drill to make vent holes too small for the snakes to get through but large enough to allow ventilation between sides. I just converted a 20 gal long to a side mount with a plexiglass slide door. I made the mistake of starting out with thin 1/8th inch and it cracked when I tried to cut it, I had to get 1/4 inch. you can use aquarium sealant to secure the plexiglass divider but you will need to house them in something for a good 48 hr plus till the tank sealant is fully cured and it's probably not worth it if it's just temporary.
Thanks, I'll take a look at Lowes in the morning. Money wasn't the problem, just how much room I had available. I'll get a proper tank for the second snake soon.