First of all, if you really want to do something, you'll find a way. It's possible. As non-trad myself, let me also say that there are tons of others out there like us:
http://www.oldpremeds.org/ is a veritable goldmine of optimism and practical info.
Lots of competitive MD programs accept non-trads, I saw a documentary the other day featuring a 35 year old first year at HMS. Obviously it depends where you get in your pre-reqs, assuming you didn't take them in undergrad (or, if you did, how long ago?), and other factors, like academic research, having shadowed a doctor, etc.
I'm not going to lie and say there is NO age bias (different programs differ in this regard), but know that sometimes it works in your favor. Older candidates have a lot more to lose by taking themselves out of the work force for X years --at least 5-- than trads who go straight to undergrad, with no family concerns, etc. So the committee knows, at the very least, that you want it really badly. If you're capable is another question, one that MCAT/GPA can help answer.
Finally, playing devil's advocate, med school is very different than B-school or law school, in which the ranking of the school basically dictates earning potential afterwards and the ROI of the degree itself. With med school, however, you can go to pretty much any school (Caribbean ones excluded, perhaps-- although I know of one lady who got a residency at H-bomb afterwards) and be a competent doctor with as much earning potential as the next guy (specialities and academic performance held constant). The better med schools WILL help with residency placement, but yeah, that's that.
I'm not an expert, but these are my thoughts based on the research I've done. Good luck to you.