As best as I can tell, current surveys for individual Dyson swarms rely on IRAS and as best as I can tell the range is about what you say.
So there are two points worth making here:
1. This is, as far as I can tell, pretty similar to the range SETI is looking at. The power required for signals beyond that range to be detectable by us starts to get to a significant portion of stellar output, at which point you either have to assume such a civilization is is capable of the kind of astro-engineering we could otherwise detect and why are they outputting something with that much power?
2. On the Kardashev scale, you have K1 civilizations who use the power output of an entire planet (10^16 Watts in the Carl Sagan scale), K2 is an entire star (10^26 Watts) and K3 is an entire galaxy (notionally, 10^36 Watts). A K3 civilization is envisioned as Dyson Swarms through an entire galaxy (although, "civilization" is a loose concept when there's light lag of 100,000 light years from one end to the other).
I found a link to a study of 100,000 of the nearest galaxies looking for that kind of IR signature on a galactic rather than solar level. No evidence has yet been found.
The gap between a K2 and.a K3 civilization is actually not that large.