I think it is probably pixelperfect.....
has more css, less images. You can make it faster by stripping the color switcher, font resizer and anything else you don't need also.
Just an opinion.
Do not go where the path may lead, go instead where there is no path and leave a trail.
pixelperfect, primetime & glossypaint, blogtopia. these all make minimal use of extra scripts and template related graphics. going to the template demos and loading them all might give you a good idea too.
forgive my Firefox newbness but how do you see how long a site takes to load in it?
getfirebug.com/ 
; It can monitor exactly how long each element of your page takes to load. So if there is a problem or something is bloated, you can see exactly what the problem is.