vja4Him, you're getting some great advice here. I'm glad you're reconsidering your desired top speed...25-30mph should be more than enough for a commuter bike. Once again, I'll vouch for my AmpedBikes kit shown over on Endless-Sphere that you posted on. Mine is 37v and does 22mph, but if you up it to 48v and 15 to 20 amp hour rate, it would fit your needs perfectly (28-30mph with 20+ mile range), all at around $1100 for the rear wheel kit and LiFePo4 48v 20ah battery. And you could make your own custom battery box to fit inside the frame like I did. My setup is perfectly balanced like that. It's a real joy to ride.
You might want to add AmpedBikes to your consideration list.