Is there any FAA reference that recommends or specifically allows for the use of a coupled approach (such as autoland) when the pilot is specifically cleared for a visual approach?
The general answer is no. A visual approach isn't considered an instrument approach according to ATC so there's no restriction - or direction, if you prefer - on how to fly one:
A visual approach is an ATC authorization for an aircraft on an IFR flight plan to proceed visually to the airport of intended landing; it is not an instrument approach procedure. Also, there is no missed approach segment. An aircraft unable to complete a visual approach must be handled as any go-around and appropriate separation must be provided.
And from the AIM 5-5-11:
The pilot must, at all times, have either the airport or the preceding aircraft in sight. After being cleared for a visual approach, proceed to the airport in a normal manner or follow the preceding aircraft. Remain clear of clouds while conducting a visual approach.
That means that when you're cleared for a visual approach it's entirely up to you how you approach and land, providing that you follow the rules mentioned in the AIM and - in the case of airline operations - whatever procedures are detailed in your operations specification.
But if you're asking about autoland specifically (not general autopilot use) then the FAA does have a few relevant comments in their guidelines for CAT III operations:
Autoland or HUD to touchdown operations are required for all CAT III operations, and many operators use autoland or HUD for CAT II, CAT I, and visual flight rules (VFR) operations as well. Part 121, § 121.579(c); part 125, § 125.329(d); and part 135, § 135.93(d) prohibit the use of autoland or HUD to touchdown in any operation unless the operator is specifically authorized via OpSpecs.
Practice autoland or HUD to touchdown operations may be conducted at CAT I runways in CAT I or better weather conditions where the facility classification is unknown, because the flightcrew is monitoring system performance, visually verifying the position of the aircraft, and can determine whether to continue to a landing or execute a missed approach in CAT I or better weather conditions. Though it is not recommended, flightcrew monitoring and increased visibility also permits practice autoland or HUD to touchdown operations using an ILS classified as I/A, I/B, I/C, or I/T, provided the operation is performed in VFR conditions
I understand that to mean that autolanding is allowed in visual conditions (provided it's authorized via OpSpecs) for training/practice purposes, and since they mention autolanding use even under VFR I don't see why it wouldn't be allowed on a visual approach.