At least qgis and merkaartor currently bundle this library:
http://hub.qgis.org/projects/quantum-gis/repository/show/src/core/gps/qextserialport
http://www.merkaartor.be/projects/merkaartor/repository/revisions/master/show/src/qextserialport

Already submitted patch for QGIS: http://hub.qgis.org/issues/6613

Also qlandkartegt:
http://qlandkartegt.svn.sourceforge.net/viewvc/qlandkartegt/QLandkarteGT/trunk/3rdparty/SerialPort/

Volker found a handful other upstream projects which use this, but it looks like only the GIS stuff is already in Fedora.

formal review is here, see the notes explaining OK* and BAD statuses below:

BAD     source files match upstream:
            cc9e91f6e1bec987616066902fbf532937b120e5  qextserialport-1.2beta2.tar.gz
OK      package meets naming and versioning guidelines.
OK      specfile is properly named, is cleanly written and uses macros consistently.
OK      dist tag is present.
OK      license field matches the actual license.
OK      license is open source-compatible (MIT). License text included in package.
OK      latest version is being packaged.
OK      BuildRequires are proper.
OK      compiler flags are appropriate.
OK      package builds in mock (Rawhide/x86_64).
OK      debuginfo package looks complete.
OK      rpmlint is silent.
BAD     final provides and requires look sane.
N/A     %check is present and all tests pass.
OK      shared libraries are added to the regular linker search paths.
OK      owns the directories it creates.
OK      doesn't own any directories it shouldn't.
OK      no duplicates in %files.
OK      file permissions are appropriate.
OK      correct scriptlets present.
OK      code, not content.
OK      documentation is small, so no -docs subpackage is necessary.
OK      %docs are not necessary for the proper functioning of the package.
OK      headers in devel subpackage
OK      no pkgconfig files.
OK      no libtool .la droppings.
OK      not a GUI app.

- please use the whole URL for the source archive - http://qextserialport.googlecode.com/files/qextserialport-1.2beta2.tar.gz works here, otherwise a comment is needed
- the devel subpackage should depend on qt4-devel, because %{_qt4_datadir}/mkspecs/features/
    would be unwned otherwise, also it's unusable without qt4-devel
- I prefer trailing slash when whole directory should be included => %{_includedir}/QtExtSerialPort/

Argh, those were stupid mistakes!

Spec URL: http://www.geofrogger.net/review/qextserialport.spec
SRPM URL: http://www.geofrogger.net/review/qextserialport-1.2-0.2.beta2.fc16.src.rpm

all issues are fixed now, APPROVED

New Package SCM Request
=======================
Package Name: qextserialport
Short Description: Qt interface class for old fashioned serial ports
Owners: volter
Branches: f17 f18
InitialCC:

Git done (by process-git-requests).

qextserialport-1.2-0.2.beta2.fc17 has been submitted as an update for Fedora 17.
https://admin.fedoraproject.org/updates/qextserialport-1.2-0.2.beta2.fc17

qextserialport-1.2-0.2.beta2.fc18 has been submitted as an update for Fedora 18.
https://admin.fedoraproject.org/updates/qextserialport-1.2-0.2.beta2.fc18

qextserialport-1.2-0.2.beta2.fc18 has been pushed to the Fedora 18 testing repository.

qextserialport-1.2-0.2.beta2.fc17 has been pushed to the Fedora 17 stable repository.

Package Change Request
======================
Package Name: qextserialport
New Branches: el6 epel7
Owners: dlj
InitialCC: volter

Comments from primary maintainers?

That's fine!

Is there anything else needed before these branches can be created?

dlj is not in the packager group.

I think the user name should be daveisfera and not dlj. Please correct your request, Dave!

Yes, my username is daveisfera.
Thanks,
Dave

Request not yet corrected.

Here's the correction for comment 13:

Package Change Request
======================
Package Name: qextserialport
New Branches: el6 epel7
Owners: daveisfera
InitialCC: volter

Git done (by process-git-requests).