Could never figure that one out. My dealer had 15 IS's on the lot and not one had the Luxury Package. Fortunately he had one (just one) with the LP that was arriving within the week. Wasn't the color I wanted but I still snapped the car up right away (I'm happy with the color now, although it's a bear to keep clean). The Luxury Package actually had just about every option I wanted (except for the nav system, which I got as well). It would seem to be a no-brainer to have at least a few of the IS's with the LP around for those buyers looking for it, unless it's not as popular an option as I would like to think...
You nailed it. I had to have the Lux Pkg. There was not a Breakwater Blue one within 500 miles on the lot, or on the way. Nor could they find a Matador Red or a SGM (without black interior). It took four weeks, but they found a Tungsten/Serling one. It looks great.
Apparently, less than 10% of all IS 250s are produced with the Lux Pkg, then, when you factor in the less demanded colors, they are darned near impossible to find.