Line-item cost of one student-year on a grant?

I am in the process of writing some proposals and am encountering the fun task of generating budgets for those proposals. Rutgers, like many cash-strapped schools, imposes a hefty “overhead” charge on federal grants (the so-called indirect costs) amounting to something like more than 50% of the value of the grant. Since I’m primarily a theory guy, the largest line item on any grant I write is generally a graduate students. With stipend, tuition, fees, and benefits, a calendar-year appointment for a graduate student costs around $90k, factoring indirect costs. Given that an NSF Small award caps out at $500k, it’s quite difficult to support more than one student for a small grant. This in turn limits the scope of research one can propose — it’s all fine and well to say there are 15 journal papers’ worth of results stemming from your great ideas, but 3-4 student years is probably not enough to make that happen.

I know some schools offer a tuition break for RAs/GSRs, but I am not sure how prevalent this practice is. So I put it to the readers of the blog: what is the line-item cost to support a graduate student for one year (without travel etc.) at your institution?