using the google search function to look for (where you get your parts), wich is the same as a normal google search for (where you get your parts site:
www.candlepowerforums.com), I came up with the following as the first link that isnt this thread:
http://www.candlepowerforums.com/vb/showthread.php?265314-Where-do-you-buy-your-parts-from
there are quite a few site listed there
now when you say dimmable do you mean; a) has different settings like low, medium, high or b) can be hooked up to a potentiomiter so that it will have an on/off button and a knob that varries the light like a volume knob on a speaker? type A is common and easy to find, type B is less common but i think there are a few of those around or ways to midify things