Don't forget that you still need to spend money on the hoses and connections to bring hydraulics up from the rear remotes. I think it cost me just under $200 when I did it on my LS. So the savings aren't necessarily as drastic as you're indicating.
Personally, I'd prefer spending $500 on an electric diverter, like the one I use for my rears... Then plumb it to divert your curl function. The shortened hose requirement would probably equal around $100, and would therefore only cost $400 more than using rear remotes.
I'm not arguing that an electric diverter or third function isn't a reasonable solution for many people. My point is that a simple, inexpensive DIY solution is available for those who are waffling about the value of a diverter/third function installation. A grapple is so useful that adding one, even if it is just a bucket grapple, should be a priority for anyone involved in land clearing. If $3000 for a turnkey solution (grapple, adapter, third function) is out of reach, the project (with a bucket grapple) can be done for under $500 if you already have a rear remote.
Yes, absolutely you do need to buy quick connects and hoses with appropriate fittings. However those items are essentially the same as what are needed for setting up a third function valve. The only real difference is the length of the hoses. If someone bought long hoses to try out with rear remotes and then decided to get a third function valve, they just need to take the long hoses to a hydraulic shop to be cut to size and have new fittings squeezed on.
I suppose the cost of four quick connects ($25) and 20 feet of hose x2 ($80) could cost even more than $200 at a local hydraulic shop but the same things can be ordered from Surplus Supply for a bit over $100. Of course if you later needed the local shop to modify the hoses they would probably charge $50 or so to cut the hoses and put new end fittings on.
Still, at a total cost of well under $200, virtually all of it reusable with a third function set up, it is a pretty good deal. And, you can do it in your backyard with nothing more complicated than a couple vise grips and teflon tape. It took me longer to screw the various fittings on than it did to route the lines and secure them with zip ties. More permanent clamps and bulkhead plates can be added if the system works to your satisfaction.
1/2" NPT QUICK COUPLER F/F S20-4
Surplus Center
Maybe add a 90 degree adapter to avoid a big loop of hose at the rear of the tractor:
1/2 NPTM to 1/2 NPTF 90 ELBOW
And please, unless you know of examples where a tractor rolled over while UNLOADING a grapple or clamping down on a load, don't go starting rumors about how dangerous opening and closing a grapple is. Silly. Opening or closing a grapple has zero impact on the dynamic stability of a tractor as the tractor is stopped when that operation occurs. Static stability of a tractor goes up the moment the load from an elevated grapple is dumped. Your hand IS on the FEL stick while the grapple is moving up or down and that is what affects stability. It is only the opening and closing of the grapple that require moving your hand off the joystick and that only happens at rest. And, lest we forget, your hand is still within six or nine inches of the joystick. Do you also think removing one hand from the steering wheel of a car to shift gears is dangerous? Safety police require two hands on the wheel!