i think if you get the big container you could always use pond liner to line it and you wouldnt have to worry about rust and all that jazz and ittl be more attractive to the eye to look in then all metal . and if your handry enuff you could make a wood box around the metal with a good shelf so you wont need abasking area within the water but around it .
http://www.redearslider.com/habitat_gallery.html
kinda liek something like the one in the indoor set up gallery but they have used a pre formed pond but its sorta the same idea mybe that might be another way to go at this you could build an inddor pond so to say g.
go out buy a preformed pond and build a wood box that you can sink it in but make sure you fully suport it other wise i belive they can crack and leak and nobody wants to deal with that