I am a lefty also. I do this but I have shot them quite abit too. I can pick a right handed bow and shoot it left handed and shoot it pretty good. Not knocking Martin but there are alot of good bows out there that are not Martin. I would at least check out a few other brands. The good thing about being a lefty there are some very good deals on used left handed bows. If you buy one out of the classifieds and get a good deal and if you decided it not for you most the time you can get your money back by reselling.If you are just trying to feel out different bow's draw cycle then you could still draw those right handed bows left handed. I would not suggest shooting them this way because the cables will be rubbing against your forearm and you will be torquing the bow quite a bit. When you find one that you like then you can order the one that fits you in a lefty.
Sounds like me. No left handed bows in stock much less the one I wanted. I tried to get the feel with the right handed bows but it was awkward. I ended up getting one that I had never shot, drew back or even held. I will NEVER do this again. I ended up with a GREAT bow, but the fit wasn't the best for me. I probably would have gotten lighter limbs and a half inch shorter draw. I would say even if you have to take a road trip to be able to try some out, do it then you can order the right one from your local shop.I feel your pain I only have 1 shop in my area so I jsut read lots of reviews comments on certain bows and that's how I make a decision.