one man's trash another man's treasure.
I have seen threads hear on BS about "dark" combs, IMO not all that dark. So if I was to "pull" 3 frames from a hive to make a NUC, some would be dark, some would have Drone spots ,etc. To a perfectionist, some of these could be seen as Junk. So in the day, pre some of this accumulation of chemicals in comb, I would have a comb in service for 10 years and not think any thing of it. We have IMO drifted, to where culling in 5 years is somewhat expected. The chemicals rarely can be seen. So the "look" of a comb can be deceiving. For me If I got a NUC and it was on "plastic" frames I would think YUK.. as I am a wood frame type person. So I would think either ask what you should expect or offer, some build frames of you "specification" to be used. It would complicate things, but if you are a good customer I would think it would be allowed.
To the OP original question, Selling NUCs is "comb consuming" so some math and a plan would need to be in place. Frames by the 100 are about a buck per as well the wax so 10$ of your inputs is the 5 frames w/ foundation.
IE sell 10 NUCs in 2021
need total of 50 additional frames
likely need at least 30 built out with bees.
need 10 temp NUC boxes. (or do 2 batches of 5)
ETC so make a plan.
So add 3 deeps of foundation to the hives you intend to take the bees from, the previous july and in the spring, if they survive you would have the comb, with bees.
Palmer style NUCs would supply build comb as an option.
One could use deeps for supers and extract
Some folks plan to keep on all mediums,, so maybe Medium frame NUCs could have a market as well. Unfortunately they have the same inputs for 1/3 less comb and bees. Maybe an 8 frame medium for 12 bucks more would get the hive started well and give you a second product.
I would start slow maybe 10 the first year , 20 the second, and work the kinks out of your system.
Do get payment up front, do have a "wait list" with a few names for cancellations. Example, Today in Michigan 3 dams burst and 10,000 people were evacuated, any plans they had are down the river so to speak.
Do make a few extra in case you have a dud queen.
Could offer a "do you want fries with that service" where you bring the NUC to their place and move it into their hive , show them the brood and queen etc.
Try to fill the need, it may or may not be what you think.
good luck
GG