Like you, I like the 6.5 caliber. I think it is the ideal trade-off between long range performance (high BC) and acceptable recoil for a non target weight gun. It is popular and there are lots of good bullets in the 130-140 grain range. I have had two .264 WM's but I really cannot recommend it. They pack too much powder for the bore and don't make for a long accurate barrel life. Some may beg to differ, but that is my experience. I am currently waiting for a 6.5 Remington Magnum barrel to be delivered, which I think has a much more efficient case capacity of 68 grains instead of the .264's 82 grains. You can get quite close to the same velocity along with better barrel life. However getting good brass or even any brass for the 6.5 RM is a problem, and I can't recommend it for that reason. The 6.5x284 has become quite popular in the long distance target shooting world because of the lower recoil and long distance ballistic performance. Lapua makes brass for the 6.5x284 for that reason. The ironic part is that if you want .284 Win standard brass from Lapua you have to neck up the wildcat to get the old original cartridge!
The reason I say long action is because those 130-140 grain bullets are getting longer and longer to achieve the low drag long distance performance. Some are now nearly 1.5" long. The nose sticks out a long way from the ogive, and if you want to seat to the ogive your COAL is very long. I expect my 6.5 RM loads to be around 3 3/8" overall. You need a long action for that, and my new barrel will go in a long action Remington 700 (that used to be a .264 WM). For target shooting you can single feed to somewhat get around that, but for hunting you want your rounds to fit the magazine.
You need 8 to 8.5 twist for these new long bullets to stabilize. 24" is to preserve your velocity, and 26" would be better. 416 stainless provides a bit better barrel life, and the 6.5x284 is still not going to be a 3000 round .308 type life.
Hope that helps some...