yes, they do have just a 1/2" spacer. lets say you get the toyotec 3", it comes with a 2.5" in coil spacer and another .5" lift that goes over the top of the coil assembly.
here is an example.
http://www.toyteclifts.com/images/pr...4topspacer.png
it's 59.99 from toyotec,
Tundra Shopping Cart for Toyteclfts.com, and you will need to remove the strut support and replace the studs with newer, supplied, longer studs. scroll down to the "top plate spacers/stud"
you can probably get away with just installing them for the fronts, as the rear will need something different, an add a leaf or lift shackles.