I have 1156 (S25-36led lights) base led lights I use for backup lights on my lifted truck. They are superwhite and have 36 led bulbs. I previously had xenon 1156 bulbs and these led's are about twice as bright(in my estimation). I bought them from www.ledlight.com they are $13.99 each and the SKU# is 49785W1165. I might add that I have bough quite a few other led lights from these guys and thay are good to deal with. I have led sidemarker lights, 1157's, interior lights, and bulbs on the exterior of my house they have all worked flawlessly. The only other thing that I will say is that these 1156's are a VERY intense light. They also offer softer color led's that would be better suited to interior use. When I back out of my driveway they light up the house across the street like a bright flashlight. I will soon own a 78 dolphin and plan to change the DC bulbs also.
This should be the link to the exact bulbs I have. There are some more powerful options also
http://www.ledlight.com/s25-36-super-bright-led-light.aspx
Good luck, Clayton