Not being as well educated on matters of taxation and school financing as Andrew, what strikes me about proposals that include school busing is the way in which progressive strategies wind up harming those whom they are ostensibly (cynically?) promoted as helping.
In constructing a society an environment in which individuals, families, and communities are able to improve their standing, perhaps the most critical component is predictability. If a family works and saves in order to buy a house in a higher-quality school district, it must be certain that its children will benefit from those schools. Similarly, if a community raises funds and passes legislation to improve its schools, it must be certain that its children will benefit from those improvements. This consideration applies regardless of the particular benefit being sought, whether it is scholastic or of the sort that is sometimes left unsaid for the benefit of tender sensibilities.
People will not strive if, having striven, they might lose by lottery what they could win by lottery while doing nothing. Moreover, those in the supposedly privileged group will cease to participate in and finance a local system from which they can find themselves randomly excluded or, worse, targeted for exclusion. And one or the other of these possibilities must be the case; either the students to be displaced will be randomly selected, or they will be chosen, probably with heavy consideration given to their particular stereotypes in a "socioeconomic diversity" index. As the more privileged students move beyond the system's reach, the burden of the new scheme will fall, as such burdens seem often to do, on families that are just beginning to achieve momentum.
The tragedy is that society could achieve its professed goals more smoothly, more organically, and more stably (albeit, perhaps over a greater period of time) by removing barriers and disincentives to advancement, rather than institutionalizing obstacles and backslides. We could ask for no better ballast for social progress than human nature (and, despite attempts throughout history, we cannot deny it, anyway). But one gets the impression that the progressive mind sees people not as individuals capable of self-determination, but as slaves shackled to their circumstances. At the least, they must be concerned that people who credit themselves with the progress that they've made in life will be less inclined to accede to the schemers' plans.