Yup, it is currently done everyday, all over! I am an RN at a Skilled Nursing Facility that has plenty of LVNs, and even I work the floor on a daily basis. I do all the things that the LVNs do (med pass, treatments), and in addition, I hang IV medications.
LVN's cannot hang IV medications. Even if they are IV certified, the most they can do is IV starts. For this reason especially, Skilled Nursing Facilities will always need RNs! Further, there is such a great market for RN jobs in SNF because most RNs are flocking elsewhere (e.g. to higher paying jobs and/or jobs with smaller patient ratio). It can be very challenging for SNFs to snag enough RNs.
However, I have found that in some cases, you can make a salary that would be comparable to hospital. This is because in SNF there are always opportunities for extra shifts. In fact, I'm in the middle of working 8 days in a row as we speak!
My earnings are through the roof right now, and working this much is not even all that hard on me because I enjoy it. It's a job I like. I feel very challenged. The shifts go by incredibly fast. I get great exercise while I'm there. I love taking care of my patients, who are like my family. I have fun with my coworkers, and feel comfortable with them. This kind of work gives my life meaning and purpose. I count it a blessing that I get to wake up and do this everyday, and get paid for it! I couldn't ask for a better life.
I'm grateful for the opportunities that SNF provides for RNs. There really are some fantastic facilities out there, you just have to find them.