well... we cant make any decisions for you... have you tried the racquet finder utility on this site?
I think anything below 65 flex is a good flexible racquet. To be honest, arm problems comes more from bad form than anything. To avoid arm problem, definitly stay away from 70 flex rating racquets... but in all honesty, I had just about EVERY kind of arm pain from my wrist, forearm, shouder... and they were bad to a point where I could barely play. and the racquet I used ranged from the super stiff Triad, still rather stiff Airlaunch, to the flexy Pure Storm. and I had arm pain with all 3 racquets, the only racquet I havent had major arm pain with is the Diablo Tour I use right now, but thats probably because my level of play improved. here are the causes to my arm pain...
1)Mis-hits... those, especially because I have a rather fast swing speed, hitting balls on the frame KILLS your arm faster than anything, everytime I hit a framer, my arm would be in pain.
2)too wristy... I use to not know how to transfer my weight, it was a pure wrist shot, no leg and my wrist and forearm killed me all freshman year.
3)full poly strings... just stay away from those, and babolat hurricanes... or just polys all together.
4)I was weak... my freshman year, came in at about 90 lbs and couldnt lift a chair... that was a big problem.
so as you see, I honestly dont even rank my racquet as one of the reasons of my arm pain. I think whats more important is work out and get stronger, fitter, and have a good form is what you need to avoid arm problems.
with that said... picking out your racquet is difficult too i know... first of all, a heavy racquet is always good. demanding? maybe... but I mean, a PS85 is demanding, but most MP racquets are not so much. I think anything around 100 sq-inch is a good fit. and 11.5 oz... but I know when I was a freshman, I couldnt have used anything above 10.5 oz. but if you think you have no problem swinging a 11.5 oz racquet around then it shouldnt be an issue. I'm not a strong person by any means, but my diablo comes in at about 12 oz and its working just fine. I mean still crank a serve at around 100 mph... (ok a little less).
I hope you read what I had to say before you jumped down to the list because the list is VERY subjective... you really have to demo them before making a decision. these are just what I like and think are good frames. no one here hit with every frame on the market and likes the same frames you might like so you cant take our words for anything.
okay, I just went back a page...
I dont know if you mentioned your level of play... but I would recommend a tweener...
Babolat Pure Storm - this is the flexiest of the babolats and I played with it. it is NOTHING like all the other stiff babolats.
Prince O3 Tour - you could go with white, but I have hit with both and feel that the tour has more feel because of the thin beam, you might like it.
now the Tour is a "players" frame but I know a 10 yr old, 4'5 who uses it so I mean... dont let the "demanding" factor fool you.
and if you want power, TAKE LESSONS, PRACTICE, racquets will not make you hit harder. for me, if I were to switch to my purestorm again, which I tried recently, my shots would sail way long without control and I did NOT feel any improvement in my power department.
so pick your racquet by feel and comfort... not the specs...