On the power outage you need to make sure the sump can hold about 1 inch of the surface area of the main tank. I had a 72gal tank with a 20gal sump and it was close when the power went out.

Also look at Acrylic Sumps. They can be custom to your exact needs. Several Companys do Custom Sumps. You can also get combo Sump/Refug.

Good Luck.