Trailer for a TC as a stopgap until getting a one ton?

I’m in the Calif Desert right now, and so far I have seen two of what .your describing. Both on duel axel trailers that are long enough that they also have their Side X Sides loaded on the back of the same trailer, so yes people do it.
Not sure how they load the camper on the trailer..... but there is such a combo out in the world.
Soup

Yes, you can trailer a tc, but it needs a stout trailer. The question is why though. You probably can buy a travel trailer for less.

I see them quite often on either a pickup bed made into a trailer or a flatbed trailer.My neighbor has an Arctic Fox that he mounts on a long flatbed trailer then he loads his UTV's behind that.When he takes the UTV's off,he has a nice deck behind the TC.Kinda neat setup..

A guy can buy a used pickup camper much cheaper around here than a small travel trailer, and pickup bed trailers are a dime a dozen..But one would need a heavy duty trailer to haul a TC on same as choosing a pickup.The 3/4 and 1 ton pickup bed trailers are hard to find.

It is pretty common. Google cabover camper on a trailer and you will see all sorts of set ups. As for a trailer built specifically for a TC I don't know if that exists but certainly can find or build one to work. A few reasons why are utility trailer tags are a whole lot cheaper than TT tags and it can make it easy to take the toys along and when the toys are unloaded you have a built in deck or dance floor.

Careful with utility trailer in CA and probably in other states as well.
Having commercial registration on your truck, you should declare max GCWR at registration and display weight sticker on your door, or pillar.
That will also push you via the scales and checking trailer emergency brake systems is red flag for DOT.
RVs are exempt.

I think it would work.
One issue may be if the overhang is lower that the floor, you may have to put it on some sort of platform to raise it.
Most tandem axle trailers have 2) 3500 lb axles or even 5000 if you want. Either would be more than enough for any TC.
You would be looking around 3000-6000 lbs total so most 1/2 tons should be capable.
May be a challenge loading as the trailer is probably too wide but you could alway back under as far as possible and set the TC on pipes and remove the jacks and “roll” it onto the trailer.
Adjust the location for the best COG and tie it down.
The advantages would be that you could buy a quality heavy duty trailer and have a nice deck depending on trailer length.
You can get the TC you want now and wait on the truck. Maybe you will like this setup and stay with it.

July 18, 2015, Summit Lake State Park, Indiana:

I usually see this done on goose neck style trailers where the cabover fits nicely over the hitch. You will need at least a tandem axle trailer to be able to hold the weight of the camper, trailer, and contents. Many TC have sewer drains coming out the bottom so you will need to either block the camper up off the trailer or cut a hole thru the trailer floor for the drain.

It's called a "redneck 5th wheel", and yes, it's done all the time.

Still gotta tie down the camper to the trailer.

Has anyone done such a thing? Even though 4000 pounds will crush a half-ton truck if plopped on the bed, even adding a ton for the trailer is still within tow capacity.

Very common around here and has been since truck campers hit the streets in the late '50s/early '60s.

Car haulers/utility trailers usually come 7k gvwr with tandem 3500 lb axles with 15" D tires. The ones I've had weighed in the 1800 lb range leaving it with a around 5200 lb payload. Now subtract the 4000 lb camper leaves you with 1200 lb for more junk.

Next size up is a 10k gvwr with 5200 lb axles with 16" E tires. My 10k gvwr 18' car hauler weighs 2480 lb leaving it with a 7500 lb payload.

We have pipe top trailers....angle iron top trailers and flat deck car haulers types.
Make sure whatever trailer you choose it has plenty of reserve capacity for the trailers axle/tire/wheel capacities.