Alright, let's deal with another hypothetical aspect of this question then.
We all know that AMCAS has a centralized database that monitors which schools each applicant applies to and their fate (accepted, rejected, waitlisted) at each of these schools. This is the source that each school uses to figure out if people holding acceptances at their school post-May 15th are also listed as holding spots elsewhere. As of this moment, I think it is safe to assume that the OP is holding a spot at the school at which they were accepted.
I find it hard to believe that this information would not follow the OP into the next application season. It would be foolish for schools not to check those that they interview (if not using this information for primary or secondary screening) for previous application cycles. I would also be surprised if they did not have some curiosity as to what kept the OP from matriculating to school a year prior.
Now I am aware that there are plenty of success stories in years past of people reapplying and being accepted at different schools, but I think in this particular case it is a bad idea for two reasons. First, these other cases were mostly special circumstances. Dying family members, spouse career opportunities, and the such are viewed as legitimate excuses for turning down an acceptance. I find it hard to believe that the lack of foresight to investigate the research opportunities at a school (especially your own undergraduate institution) would be viewed as such an overriding circumstance. If anything, it would just paint a picture of a sloppy applicant.
Second, if the OP is a state resident of the school at which he already was accepted, and if there are not a great deal of schools in the state, he is seriously cutting his chances down of acceptance.
No matter how you paint the picture I think it is clear that in this seemingly random process putting yourself back on the market is a huge gamble. The great boost of confidence you are no doubt experiencing following your acceptance may make you feel invincible at this point, but given a second opportunity the fates may not be so kind. What then?