http://www.somdnews.com/stories/03032010/entetop162900_32193...
(The richer suburbs, e.g. Charles and St. Marys spend $3-5k/student less than Baltimore schools.)
There's a considerable amount of research done on the effects and nature of funding disparities, if you haven't looked into it, I'd recommend it.
http://www.bcps.org/offices/PAYROLL/pdf/scales/TABCO-12-Mont...
http://www2.ccboe.com/employment/Teacher-SalaryScale-1011.pd...
http://divisions.smcps.org/hr/sites/divisions.smcps.org.hr/f...
I've heard many assertions that inner city and other underperforming schools are underfunded. But whenever I go to look them up, and compare them to the rich suburbs, they seem to be wildly overfunded. Baltimore seems to be better funded than the rest of Maryland. Newark and Trenton public schools are funded better than most of NJ, and perform terribly.
But hey, you've got vague allusions to a "considerable amount of research". That's more useful than hard numbers.
There's also the issue, unaddressed, of extra per-student costs. For instance, special needs students can be very expensive, often requiring one-on-one instruction, which can greatly skew the per-student costs.
And saying that unions need to be reformed in different directions is very different from saying that unions need to be done away with.