Below is my highly modified Lg. ALICE pack, the best pack I've ever used.
I bought a "Hellcat modified" Lg. ALICE many years ago for $150.00 because I knew the toughness firsthand of the ALICE system, having carried a Medium ALICE during my time in the Marine Corps. I didn't use my Lg. ALICE much though because my commercial North Face Crestone 75 was lighter and had plenty of room for even Winter ground camping.
Now that I'm a bit older I find sleeping in a hammock much easier on my old bones. Unfortunately in Winter that means adding a lot more gear to stay warm or suffer "CBS" (Cold Butt Syndrome) so having gone to Winter "Hangs" I started looking for a larger pack to fit it all in.
After looking for several weeks and realizing that the average cost for a MILSPEC pack was going to be above $400.00 on average, I took a look at Tactical Tailor's pack modifications and eventually took that route. I was able to increase the cubic inches by 30% and increase compartmentalization to allow for easy access, all for less than $100.00 using a TT's Military Discount.
A 92 LITER MONSTER!
Anything over 60L is considered by most to be a large pack, at 90+L some would say you have gone to "ludicrous size" in a pack. The important thing to remember is that having space DOES NOT MEAN you must stuff it full.
The advantage the large space gives me is the ability to carry large lightweight items like sleeping bags, under-quilts, freeze-dried meals, etc. during Winter.
The advantage the additional pouches gives me is easy access and repeatability of finding items without light. I think this gets overlooked way too much with the modern single compartment designs most packs use.
FRAME MODIFICATION
The original ALICE frame is a fairly sturdy one, but was built for people of a 5'-8" frame. It tends to cause the kidney belt to ride above the hips instead on on them like most modern pack belts for those of use over six foot.
I first read about this modification on a thread at the BushcraftUSA forum and decided to extend my own as I'm 6'-2" now and while I've not had huge issues with the stock frame, I wondered how much better it would fit if extended? Those who have done the mod said it made a huge difference so I went for it.
Once I cut into the frame I found an inner tube with a 0.500 OD and an outer tube of 0.510 ID of aluminum. So instead of adding extensions between the two cut pieces as I had originally planned, I decided to replace the bottom tubes going to the bottom shelf and weld all riveted stress connections for strength.
I purchased two 48" sticks of 6053 aluminum off Amazon that were:
Aluminum Round Tubing - 5/8" OD x .050" x 48" Long $11.80 delivered
Aluminum Round Tubing - 1/2" OD x .050" x 48" Long $10.50 delivered
One person who was using the extended frame mod said he was 6'-4" and an additional 4" was perfect for him, so I decided to go with a 4" extension also and weld every connection point that used rivets. All the rivets were loose on this frame and the top one had popped out.
After TIG welding, it feels like one solid piece with no movement. The reflective piece in the center (1.25"x.125") is cut from an old STOP sign I had and it very "springy" just like the original brace was.
So for less than $25.00 and some welding, I got a frame that actually fits a taller person.
I immediately noticed that the pack was now sitting on my hips instead of the kidneys, the pack sits more upright and does not pull on the shoulder straps as before and the affect of which is a "lighter" feeling pack.
Don't count the old Veteran ALICE out of considerations, especially is you already own one. For less than $270.00 this finished product packs a lot of "bang for the buck" even in today's market.