try <a href="http://www.garf.org" target="_blank">www.garf.org</a> they have a link (you'll have to run a search for it) called "140 gallon aquarium construction". it gives the instructions on diy tanks for plywood and glass/acrylic. don't know how well it works because i've never tried it, but it looks do-able.
after you run the search, you'll end up at a page w/ 240+ links. one is "tank/ build tank.asp" and the other is "garf's reef aquarium construction- 140 gallon aquarium" (sorry. i don't know how to do advanced links
) but this should help. <img src="graemlins//angel.gif" border="0" alt="[angel]" />