The characteristics of tokamak demonstration reactors (DEMOs) that would extrapolate from both the existing and the emerging physics and materials databases are calculated. The emerging advanced physics design base would allow more compact DEMO designs at lower plasma currents than would be possible with the existing physics design base upon which the International Thermonuclear Experimental Reactor (ITER) is being designed. The primary structural material for ITER, 316SS, has a relatively low first-wall heat flux limit, which probably would preclude full utilization of the emerging advanced physics database in the DEMOs. Furthermore, the use of 316SS would lead to DEMOs that required deep repository burial of radioactive waste upon decommissioning. An advanced structural material (e.g. V-4Ti-4Cr) would allow fuller utilization of the advanced physics design base and would lead to DEMOs that possibly would satisfy near surface burial criteria