The QA frames are quite reasonable at auctions. This one was purchased at Ritchie Bros. Auctions and a log carrier built on it. They have actions all over the world. An auction yard is only 20 miles away from my place. Maybe you can find something similar.
The cheapest frame and fork combination I've seen around here is about $500 used,
for a Skid Steer, and its heavy, and I 'd have to get it adapted to the Kubota Pin QA.
The new Kubota Pallet frame, for the Kubota Pin QA, is $544.00 at 145 pounds,
and the 36" pallet forks are $350.00 at 154 pounds.
Total $894.00 at 299 pounds. These are 6 year old suggested retail prices.
So with time and fluctuating steel prices, actual cost maybe differant now.
This is the Frame /Fork combination Kubota builds for the
B7800 tractor with Pin QA.
I would think aftermarket frame/forks could be cheaper,
but probably about the same in weight.
The Carry-All is about $135 includeing tax at Tractor Supply,
and I'd have to adapt it to the Kubota Pin Qa also, less than $50.0O for me.
The Carry-All is rated to carry 1000 pounds and it weights only 75 pounds,
and maybe it would weigh 100 pounds after QA adapters are added.
I would be able to carry 199 pound more in payload by using the
Carry-all Qa compared to the Kubota frame/fork QA.
For me, payload is a bigger concern than adjustable forks.
I have been hauling my 16" firewood from the woods on
pallets/wood racks on my 3 point carry-all,
with a homemade rack on the front,
carrying buckets of sand for front end ballast.
Now that I have a loader with pin QA,
my plan was to use the Carry-all QA attachment to also haul firewood.
The wood on my 3 point carry-all would be ballast for the loader QA carry-all loaded with wood.
I know of another
B7800 owner that uses 800 pound 3 point ballast with no problem.
I just got to make sure that I load the loader QA carry-all last and unload it first,
to insure my rear tires don't come off the ground.