"They are dead wrong, as usual..." That seems a little presumptive of my sources, don't you think? As it happens I did find some new ones though.
Verhoeven's paper on knife edge wear provides references where the steel manufacturer states steels such as AEB-L/13C26 can be heat treated to produce fine arrays of chromium carbides.
Verhoeven's book for blade smiths has an extensive section on heat treating similar steels, including the phase diagram for iron-carbon-chromium at both 1000 deg. C and 1100 deg. C. The composition of AEB-L puts it in the austenite + chromium carbide range when austenized in the 1000-1100 deg. C range.
Thermocalc is a program used to design alloys and heat treatments. It has been applied to AEB-L and the phase diagram is linked below. It is a diagram of the phases present at various temperatures and carbon contents, with the amount of chromium held constant at the nominal chromium content of AEB-L. This diagram also shows that the combination of AEB-L's alloy content and typical austenizing temperatures forms chromium carbides.
http://www.calphad.com/AEB-L.html (This one was new. I found it while looking for information from Uddeholm)
The PhD thesis linked below shows considerable chromium carbide in steels very similar to AEB-L when in the annealed condition. The steels (A & B) have slightly more carbon (0.69% and 0.7%) than AEB-L (0.65%), with similar chromium levels, along with trace elements. These chromium carbides remain after quenching, similar to the way iron carbide remains after quenching steels like 1095. Note also that the above diagrams also show that a high enough austenizing temperature will dissolve all the carbide, resulting in all austenite. For various reasons, this is not recommended.
http://iris.lib.neu.edu/cgi/viewcontent.cgi?article=1023&context=mech_eng_diss (This one was also new.)
A similar thesis shows chromium carbides present in 420HC type steel, which has less carbon than AEB-L, with similar chromium levels. I don't have a link to the full thesis. If I get one, I'll post it.
Now, to be clear, these carbides are not all chromium carbide. They will contain some iron mixed into the carbide, which replaces/substitutes for chromium. However, they are primarily chromium carbide, particularly since there are not other elements present to make carbides in AEB-L type steels. This is the reason the diagrams reference carbides as M7C3 and M23C6. The M stands for metal. It is also sometimes written as (Cr, Fe)7C3, where the first element is the primary carbide former.
Again, if you have sources that show iron carbide replaces chromium carbide, or that chromium carbide can't be formed with the steels being discussed, I would be very interested to see them.
Oh, and to be on topic to the original poster's question, there is a section in Verhoeven's book for blade smiths that outlines a procedure for heat treating stainless steels without the use of cryogenic or sub-zero treatment. I don't know of anyone that has explored it in knife making, but the information is out there.