Myself and a close friend have looked thgis caliber over and over but neither of us has actually bit into it just yet.
Even so, if I were starting off with it today, I would go for the 30-06 cases and work them down. I would probably run the necks up into a .270 die just shy of the original shoulder or far enough to just kiss it, before working them all the way down to the final size. I have found this worked quite well when sizing down 06' cases for my 25's, verses doing it all in one step.
I would most likly go with one of the 140gr bullets as these would give me somewhat the best of both worlds, I would be getting some pretty decent velocity, but have enough weight and sectional density to potentially reach out as far as I possibly wanted to (within reason) and still have plenty of energy left over. Hornady makes the 139gr SPBT which has done very well for me over the years as has the straight spire point, plus these are usually a bit ch0eaper than most of the others out there.
I would also look hard at the powders in the medium slow burn rate, and probably be starting out with RL-19 and move up and down one or two from it. I have found that RL-19 does REALLY well in calibers with this capacity and will usually give both top accuracy and velocity with the medium weight bullets. It has done exceptionally well in my 270 Win, .280 Rem, and 7mm Rem Mag.
Other than that would be primers, I have used Win WLR for so long in most of my rifle loads I would most likly start with them. If for what ever reason they didn't work out I might move over to CCI and then Wolf, just because I have a bunch I need to use up.
Hope this helps, I know it isn't much more than suggestions but that is what you asked for. There simply isn't much difference between the .257, .264, the .277, and the .284 diameters when a load is concerned, they all start off with about the same internal case capacity. If you do a bit of searching between the 25-06, .270 and the .280 and see what is working for others using them, I would figure those components would also be a decent place to start out looking for loads in your 6.5
Mike / TX