"Quite unpalatable" is a very polite way of putting it, Mr Folse !

"Livid" would be closer to where I'd be...

I just wish we'd been in touch, (or you'd been better advised) before your purchase.

Aaaanyway, ...no use crying over spilt signals.

The fact is that each location in the world of RF will interact with signal propagation and reception in its own unique way, so no radio mic system (not even the amazingly robust, digital spread-spectrum, four-frequency-diversity RF1 scheme of the XD-V's) can be unequivocally guaranteed to cover its maximum stated range.

However, the only testimony that I can personally (hand on heart) offer in this context ...is to say that I know of nothing that even comes close to matching Line 6's XD-V systems' performance per dollar ratio.

Now, down to business. In particular, the business of getting the maximum performance from your receiver/s for the minimum additional cost.

My reading "between the lines" has me thinking that your receiver/s may have been neatly installed in a location that "looked like" it should work really well.

What's implied in both Don Boomer's and my earlier advice is that subsequent RF performance seems to indicate that this "permanence" was premature, so a (probably inconvenient) reinstallation would seem to be required.

To this end, I'd suggest a "re-birthing" to yield a "re-berthing". (The decision of whether or not to mount an actual ceremony for this is entirely yours.)

1. Give birth to a receiver from its rack, attach a pair of "rubber ducky" whip antennae (each angled 45 degrees outwards to form a notional "right angle" between them)  and power it via a mains lead long enough to reach a range of its possible future "homes";
2. Now, in the absence of a willing human, you'll need to fabricate a "body-simulating crash test dummy". Use dry towels (or something similar) to centrally and vertically hold a switched-on beltpack inside a metal container with a wide open top, such as a trash can or ice bucket. This container will be your "human substitute" RF attenuator;
3. Clip and/or tape the bodypack's lavalier to a drinking straw or ruler so that it can "stand up and be counted" into;
4. Use a chair or lectern to complete this "crash test dummy" for placement at the "performance" location/s.

What we're trying to do is walk the receiver around in an attempt to find a new "home" that yields the highest number of green-lit segments in its right-hand "RF" column of LEDS.

Bear in mind that (in a permanent arrangement such as yours) access to the front panel controls will only be needed for initial set-up, so places such as high up (the maximium being with the front panel just reachable from the ground) inside a cupboard, wall-unit or wardrobe, even if on the "wrong side" of a timber wall, are quite OK, provided that any such barriers to line of sight are not also barriers to (or reflectors of) RF.

So no metal, plaster, brick or stone in the way. Plastic, timber and most synthetics are fine.

Ideally we'd like our "weird" location to yield a rock-solid, fully-lit column of green RF lights. This would mean that, subject to a more intensive "temporary long XL cable hooked-up" walk and talk test, the whip antennae won't need extending.

As you now say that we're only talking about a 50 foot range, I feel that this will almost certainly be the case.

However, in the unlikely event that a fully lit RF column cannot be obtained, the location with the highest reading will have to be the starting point for the trial to be repeated.

Only now we'd be leaving the receiver and "walking" the whip antennae around at the end of the very longest cables they can stand, being these:

https://www.globalfulfillment.net/gfsnet/(S(axswni2zj5hwdh55bvqzq3bu))/line6/10Expand.aspx?ProductCode=98-033-0016

Bear in mind that that they can be mounted "BNC connector up or down" and are light enough to be secured with things such as cable-ties or even duct tape.

It's just that they'll need to be permanently angled for best coverage, the easiest way to visualise this being to imagine this coverage as a giant apple, the apple core representing the orientation of the whip. The depression at the "apples's stem" defines the shape of the antenna's top RF dead spot, (or "suck-out") with the depression at the other end of the "apple's core" denoting its equivalent at the bottom. 

Painting over them and their fixings is also fine, provided care is taken to prevent any liquid contamination of their BNC's (first seal them with electrical tape) and only water soluble paints are applied.

If the supplied "through-connect" bulkhead mounts are too bulky, a standard BNC video "barrel" will do for connection.