You can't get the full e-bike experience on SLA batteries, though. There is a huge difference between an SLA e-bike and one with lithium.
Are you talking about e-bike motors or bike frames? If you are talking about e-bike motors then here are the ones that are popular
crysatlyte 5303, 5304, 5305
nine continent 2806, 2807
Golden motor magic pie
As a rental place, your best bet might be to go with a kit from E+ where the controller, battery, and motor are all in the rim so the customer really can't access those things very easily. They come with lithium batteries too. They also sell ready made bikes but they are pretty expensive.
Last edited by morph999; 05-07-10 at 01:56 PM.