I made some progress playing around to to see what Linspire did (and how) to allow for a Launch button like they use. Its nothing more than a code hack (they did something to the Kmenu code. I'll explain momentarily.)
We all know the files ~/share/icons/[THEME_NAME]/[SIZE]/apps/kmenu.png and go.png define the Kmenu start Icon. However in KDE its a square this image is put. In Normal size its uses 32 X 32 Pixel images. The kicker height I believe is 48 pixels. What Linspire did was expand the length of the kmenu to a rectangle. (For example 83 X 32 L X H.) They then made the image go the edges. KDE doesn't do that, it places a small border around the icon. Because of this KDE doesnt use the exact icon size for the kicker display. Instead it goes to the next available smaller size. There it reads go.png and/or kmenu.png files for it to display on kicker.
Okay I had to do a lot of playing around to figure this out but it was worth it.
Linspire modified the source code for kmenu to allow for the extra width. I am unsure if it was auto adjustable. However, I doubt it was. Rather, Linspire most likely had a set of fixed button sizes ready. Several color schemes and styles for the end user to select. They most likely had modified KDE themes with their kmenu.png and go.png files in place of the originals.
I am also of the belief that they changed the default sizes for tiny, small, normal and large in the panel. Regardless it worked and created a better look. Unlike KBFX, Linspire's button goes flush to the left on the panel and I'm pretty sure it didn't take any more resources to utilize.
KBFX gets a bit hoggish for what it is and I noticed a marked increase in startup time. Performance also lagged severely and I had problems with several functions. Besides the program really isn't ready for primetime, after some bugs get fixed even more annoying bugs would appear. In my opinion KBFX is a work in progress.
If you look at the new KDE menu demo that SuSE is distributing with 10.2
here you will notice that the SuSE start button is simular to Linspire's (at least in size and placement.) I have no idea if this is "Kickoff" (the code name for the new SuSE KDE start menu) doing that or if SuSE is doing something else. I am going to assume its "Kickoff" simply because of the association between the button and the menu. "Kickoff" will probably have to be modified and recompiled before it will work on any other distribution besides SuSE. Hopefully we will see kickoff make its way into KDE 4.
So what Linspire did was nothing more than a simple hack to the KMenu code