Given your criteria,and that the mag box is limited length,in one of PO Ackley's books is the description for the .260 AAR,which,IIRC,is a Warren Page creation.
Its simply a 6.5 mm version of the 257 Ackley.
Plenty of mag length to long seat 140 grs. More/better bullet selection than the 25's.
Myself? I'd go with the Win Fwt profile with a minimal cleanup trim off the muzzle,maybe an inch? From full blank. Frankly,the Douglas Premium I used for my .257 AI has served well. I like a light,quality foam core/glass stock.
I did my .257 AI that way. Total weight,with 6x42 mm Leupold is 7 lbs.
I tried to trackdown Hi-Tech Specialties for you. Came up with this
http://www.legendaryarmsworks.com/category-s/112.htm
Now,I have used a CRF Husky 5000 version of that action. I like it,but here is a caution. That cast aluminum guard assy. Its unique. The full width front "tang " if you will ,where the front guard screw goes,removes a larger pocket from the stock. Its not readily replaceable.
If you glass bed it,be extremely careful removing it.DO NOT pull on the trigger guard. Why? The rear of the tang will come free.You used release agent! Good!. But the front guard screw boss will not just pull straight with it. Where the hinge pin for the hinged floor plate is cross drilled through the guard is where that cast,crystaline alloy is weak and brittle.Thats where it will snap.
That's why I built my 30-338 on the Husky with the Hi-Tech stock blind magazine. Rem 700 ADL and Krag guards work good for that.