I have been working on modified readings for ELLs and have finally uploaded some of them. They are all based on Creative Commons-licensed works, so you are free to modify my modifications to suit your own needs. Just be sure you also follow the terms of the license.
Note about grade levels: If you have ever used any sort of "grade level" or "reading ease" scoring software or website, you have probably noticed that the different tests can give widely varying results. A passage might be 5th grade level on one test and 8th grade on another test. Oh, well — it is just a function of what each test stresses or how they weight linguistic elements.
I use http://readabilityformulas.com to check my modified writings. They give a consensus grade and reading level, which is based on the results of several tests. I find it a better guide than just depending on 1 test.
Another thing I try to do, especially with lower-level readings is word frequency. As much as I can, I try to use only most common words. The exception, of course, is content area vocabulary. If the vocabulary word is likely to come up in a class, than it will likely be in the reading. I think these two steps make for pretty decent modified readings. To check this, I use the The New Dale-Chall Readability Formula. I also hope to one day have proper grade-level content word lists to use to supplement the New Dale-Chall readability formula.
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.