Really? Put off graduating for a year? I don't know that I have 50K I just wanna throw away on fluff courses to boost my GPA. I thought I couldn't do a post-bacc if I already took all my pre-reqs? I'm so disappointed...what about DO schools, just as bad?
SDN uses the term "informal post bac" to refer to taking more Ugrad when you´ve already met the requirements for a BS. It just sounds more dignified than "7th year senior". You´re right, the formal post-bac programs are closed to you.
Sorry, but whatever you´re going to do is going to cost money and no way around it. Whether you choose SMPs or more Ugrad, you´re looking at another year and another 50K. I would recommend not making the investment until you know you´re good to go on the MCAT, but that´s me
DOs are easier but not a lot easier. With a 2.8 it´s still hopeless, with a 3.2 and a truely stellar MCAT? Maybe, though still probably not. Also they pretty much require you to have a letter of rec from a current DO, so be prepared to jump through that hoop.
My plan of action would be to (in order)
1) Kill the MCAT
2) Do the SMP
3) Get the DO letter of Rec and add DO schools to your very, very broad application.
Your other options are to
1) take more Ugrad, kill the MCAT and try for DO (your state school should not cost 50K/year, if you want this option see if you can take undergrad classes at your state school after you graduate)
2) Kill the MCAT and go directly to the Carribean
3) Get to over a 3.0, get over a 31 on the MCAT (but not necassarily killing it) and THEN do the SMP. This two year plan is really your only option unless you can do extremely well on the MCAT.
You´ll notice the MCAT is a common theme here. You pretty much need to do well if you want the process of improving your application to take less than a decade, so study hard.
Good luck, you can do it, many have before.