At some elementary schools, a weekly visit to the library media center is part of the specials rotation very much like art, music and P.E. In other schools, it is for one or two grade levels to help balance out the numbers for a larger than normal grade level. FYI, the state has a maximum number of students for specials classes in elementary school depending on the subject being taught and staffing levels.
Here at Hayes, we operate on a flexible schedule. The Media Center space is heavily utilized by all stakeholders - tutoring, PTSA, classes, small groups, pleasure reading, special events and yes-testing on occasion. Depending on the day, we see up to 11 classes for check-out, instruction and computer time. This is in addition to the normal drop in visitors, copier assistance requests, technology requests, etc. that are handled on a daily basis.
Studies have shown that people learn best at the point of need. Yes, information literacy skills could be taught in isolation (e.g., through a specials rotation), but collaboration with teachers and instruction at the point of need is what truly helps with authentic learning and retention of what is being taught.
I've had a taste of what it's like to be in the specials rotation when I've been in the computer lab delivering instruction for the entire 6 day rotation. I enjoyed the interaction with the kids, but I like the freedom and variety that a flexible schedule offers.