I know this is an old thread, but here goes anyway.
I have a KUIU 7800 mounted on a KIFARU frame. I bought the frame used here in the classified. I really like the KUIU packs better than any others, but the frame has too much side to side sway, which is a bigger problem the more weight you carry. I also like the way KIFARU and EXO K4 frames have separate straps for securing meat packouts to the frame, in addition to the straps that attach the pack to the frame. I have complete KUIU systems, KUIU packs mounted to KIFARU DUPLEX and LITE frames, and KUIU packs mounted on a EXO K4 frame. Using the KIFARU and K4 frames and belts with KUIU packs, you have the molle attachments for holsters or whatever you want. They all work great, some better than others.
I bought some carbon fiber 2" wide bar stock, and I am going to epoxy a 8" long section to the round bottom of a KUIU frame so that I can use basically complete KUIU system, except for replacing the KUIU belt with a KIFARU belt and lumbar pad. This basically lets you use the molle system on the KIFARU belt with the KUIU system. I am hopeful this will remove some of the side to side sway out of the KUIU system while also providing a molle system for firearms or whatever. I find KIFARU belts the best in the business for light loads to heavy loads, as far as comfort, strength, utility, and versatility. I will run KIFARU belts on every frame system, KUIU, KIFARU, or soon K4. I am currently in process of cutting the frame mounting back panel off a K4 belt, adding a carbon fiber panel to the back of the K4 pack mounting panel, and using it with a KIFARU belt. In this configuration KIFARU belt (with its molle panels that are better the K4 molle panels) and I can use either a KIFARU or a EXO K4 lumbar support.
I hunt out west, so most often I am far from the truck. If I am hunting close to the truck or just scouting, I just use a molle KIFARU belt with 3 military fanny packs mounted on it, one on each side, and one in the back. The military fanny packs attach to the molle belt on each end of the fanny packs, so you could easily add a molle handgun rig between the belt and the pack which would still make the handgun completely and quickly accessible, while providing some concealment and extra protection to the handgun. I wear a modified military load bearing vest which holds my binos, rangefinder, and radio, with a molle remote antenna mount on the back of the vest. This modified load bearing vest is what I always have on, whether I use any other pack or waist belt or not. I can mount a handgun on the load bearing vest also. I like this option, because the handgun always stays on me, even if I take the pack off. I can also put a handgun in the fanny packs on either side, or remove one of the side fanny packs and just mount a holster to the molle KIFARU waist belt. If I am hunting farther from the truck, which is most of the time, I use a frame of some sort, with either a KIFARU Cargo Panel loaded with various molle pouches and gear, or a frame with a KUIU pack of appropriate size for the distance and trip. I can pack out meat with either of these 2 arrangements. Eventually all these options will use a KIFARU molle belt where anything, including a handgun rig can be attached. If you want to make a molle rig to slip over your KUIU belt like KUIU belt pouches do, you can buy a KIFARU belt (used on ROKSLIDE or Fleabay, or new on sale right now for $29 from KIFARU, I just bought 3 yesterday at that price), cut the molle panel off the either side (or both sides) of the KIFARU belt, sew or rig some big belt loops on the back of the molle panel(s), and just slide it over your KUIU belt.
