Could you clarify what you mean by "some colleges look at your background"?
I went to a 6 year program; there are very few out there, so to preserve anonymity I'll hold off on disclosing the name. The landscape has changed too, there used to be more 6 year programs but many are now 7 year only.
I think if you apply broadly, you have a good chance of getting into at least one BS/MD or BS/DO program based on stats alone (I'm assuming you also have good LORs and enough extracurriculars proving your interest in medicine). This good chance does include you applying to 8 year, 7 year, 6 year and both DO + MD programs across the country, to increase your interview opportunities.
I'd definitely retake the SAT as you are doing, if you get >1500 composite I think your app by numbers alone is very solid.
I don't remember my GPA unweighted or weighted, but looking at my transcript from freshman to junior year, I received 32 As, and 10 Bs total.
I took 5 AP classes junior year, and 2 AP classes sophomore year (7 total before applying).
Obviously senior year no one cares about it, since it's after application, so that's not included in the above count (I did get a couple C's in senior year).
Had to login to collegeboard/ACT websites to dig these up:
SAT with Essay — May 5, 2007
740 Reading
800 Math
ACT April 2007:
Composite Score: 34
English 35
Mathematics 34
Reading 32
Science 34
English/Writing 33