Talk Polywell has some calculations of what might be achieved with the Harold White space warping work given plausible power generation and propulsion systems. This information was provided by Paul March who is working on the NASA project to try to create a detectable warping of space.
1. First have a successful creation and detection of a one part in ten million space warp
2. Develop and increase the level of space warping to a full warping of space
3. Develop advanced space propulsion to achieve about 10% of light speed (nuclear fusion propulsion, nuclear fission propulsion, power beamed propulsion)
4. Apply the advanced design of warping technology to the sublight space vehicle
Assuming we use a 100,000 kg vehicle with an initial velocity of 0.1 times the speed of light (c), with green light (6.0x10^14Hz) lasers for our warp field oscillators, a toroidal warp field cavity that has a superconductive Q-Factor of 10^8, with an input power of 1,000 GWe or 1.0 terawatt (T), we could expect a net light speed boost factor of only 4.02c. With 10 TWe input power we get a net c boost factor of 12.72c. Of course I could have used even higher frequencies for the warp field oscillators of say 1,000x the green light frequency, which would reduce these power levels by a factor of ~30 for the same boost factor, but we really don't know how to build X-Ray lasers yet.
Paul March did some more calculations with the warp-field analysis tool and found the following -