I have numerous tanks that I can let go cheap. 55, 30long, 29, 20, 10. All would make a good sump and I can build it out to your specs with the exception of drilling it. If you want to buy a bit and mail it along ahead of time I would be more then happy to give it a try. Quite a ways from you up in Bay City though.
The 30 longs are from an old MARS system and have three 1/2" and three 1" holes drilled in the back of them and are already divided into three compartments.