The DMG allows for mithral armor in medium or heavy (but not hide) armors, but only Mithral Chain Shirts and Breastplates are shown.

Adamantine armor has the same qualifications on armor selection, and all metal heavy and medium armors are present in Adamantine versions.

Missing Mithral versions are

1. Scale Mail
2. Half Plate
3. Ring Mail
4. Chain Mail
5. Splint
6. Plate

The DMG items are not included in the phase of the beta test.  Please see this thread for further information.  DMG items will, however, be included in the future.

I understand that only items in the SRD are being included at this time, which does have some overlap, of course, with the DMG and is probably causing no small amount of confusion.

However, in the SRD, the Mithral Armor entry states that all heavy and medium armors, except hide, can have a mithral variant, similar to the Adamantine variant.  In the current version of the software, only two of the Mithral variants exist, whereas all the Adamantine versions of armor  have been generated (as well as so many of the other various variations on the standard armor).  It is this issue to which I wish to draw attention.  

I see this exclusion a lot on other sites using the SRD, because, I think, they call out two variants as special cases (able to be worn under clothing), which are both listed in the current version, and so skip generating the other variants.  Bilbo has had a lot of influence on how people think of Mithral.

I brought it up simply because of the oversight it often is, and since the information from the DMG being added latter could possible skip over it, since some mithral armor has been generated from the SRD material. 

Thank you for your attention in this matter.  Looking up items here is so much easier than other existing resources.

Ah I see.  Thanks for the clarification!  Might I direct you to this thread to re-post your comments?  It might actually garner more attention in there.  :)

Will do, thanks!