Yes, I have the NA28 but sadly no apparatus.

Don't hold your breath. I do not believe the stand alone will include the apparatus either. The only apparatus for NA came with the SESB which is not being updated for Logos.

From your Daniel Wallace link:

"The text of the Catholic Epistles is analyzed on an entirely different
basis than the rest of the New Testament. Gerd Mink of INTF has been
developing a new textual method called the Coherence-Based Genealogical
Method or CBGM."

Here is more information about that, from Review of Biblical Literature; unfortunately, the link to the review is broken at present. You can use the link to download the 16MB 577-page PowerPoint presentation of the explanation of the TC program.

"...The final essay, and the culmination of
the volume, is Gerd Mink’s extensive introduction and discussion of the
CBGM, a computer-assisted program designed to identify genealogical
relationships between texts. The CBGM is well-known for its complexity,
and it has become a regular observation that only a handful of scholars
outside of the Münster Institut really understand it. I think the
colloquium was meant to be a step toward remedying this situation,
especially since the presentations were in English. Unfortunately, the
present essay probably reinforces the impression of the CBGM’s
complexity and probably is too difficult for many readers to read as an
introduction. Consequently, readers lacking experience with CBGM would
be well-directed first to Mink’s “Introductory Presentation,” a
thoughtfully produced 577-page pdf of a step-bystep classroom
presentation of the CBGM (http://www.uni-muenster.de/INTF/cbgm_presentation/download.html);
the presentation reflects good pedagogy and is a worthy two- to
three-hour investment of the serious text critic’s time.... Given that
the CBGM has already influenced the text of ECM and factors in a portion
of the Nestle-Aland 28th edition, the text critic who does not become
well-acquainted with the CBGM runs the risk of being left behind, making
this essay all the more indispensible to the discipline.

"I
suggest a reading strategy of (1) reading the article patiently through
once; (2) rereading the first six sections, with special emphasis on
section two (“A Brief Explanation of Basic Terms”); (3) continuing the
second reading in conjunction with the published fascicles of the ECM;
and (4) dabbling with the “Genealogical Queries” suite of programs
available online at http://intf.uni-muenster.de/cbgm/en.html, following the examples in the essay."

- From http://www.bookreviews.org/pdf/8381_9175.pdf
The Textual History of the Greek New Testament: Changing Views in
Contemporary Research Wachtel, Klaus and Michael W. Holmes, editors -
Review by James Leonard

Bruce Dunning said:

Too bad to hear that there is no plan for an NA28 apparatus.

Not sure where you heard this, can you confirm? The last I have seen from anyone Logos-authoritative was Rick Brannan in this thread, and he said, "The NA28 apparatus is not available electronically at this point."  That's much different than "no plans", I would be very surprised if it became available and Logos never included it  - just my opnion though.

http://www.nestle-aland.com/en/extra-navigation/digital-editions/

The »Nestle-Aland« for the digital age

Work with your Novum Testamentum Graece: At your PC or Mac as well as on your smartphone. Your NA28 is always at hand.

All digital editions of the NA28 include the following features:

• With transcriptions of the most important manuscripts
• Text variants displayed in the context of the respective manuscript
• Memofunction so that you can make your own notes

Nestle-Aland digital will be available as download for Microsoft Windows, OS X, iOS and Android in 2013.

From the image at Crossway of the NA-28/ESV diglot, it looks like the variant readings in the apparatus are fully spelled out - no more abbreviations for words:

http://www.crossway.org/blog/wp-content/uploads/2012/11/Screen-Shot-2012-11-15-at-8.41.51-AM.png

This fact wasn't quite clear to me from reading the NA-28 page: http://www.nestle-aland.com/en/the-28-edition/revision-and-correction-of-the-whole-edition/
but I guess that's what "Unless there are particular reasons not to do so, the variants of
consistently cited witnesses are given in full, even if they differ from
other consist- ently cited witnesses in detail only" means.

I wish the UBS4GNT apparatus were in Logos. I guess you can scroll Metzger's Textual Commentary with it, but it's not the same thing. Also, I wish the NA margin cross-references were included with NA-27. Unless I'm missing something, linking it to The Treasury of Scripture Knowledge is the only reasonable substitute for verse cross-references with NA-27 or any Bible for that matter.

Eric Weiss said:

I wish there were a way to get it to display in the window or a separate window, or wish the Apparatus superscripts were more prominent and more easily visible.

Use powerlook up.