I have been recently working on a web interface to notmuch.  The past two
weeks, I have used it as my only email client and since the trial period
was a great success (I had no major issues or problems and never had to
revert to another client), I have decided to release an initial version.  I
am planning on continuing to use this web client as my sole notmuch client
and will continue developing features (most identified by my two week trial
period :)  Combined with the It's All Text Firefox plugin for compose, I am
really happy with the result.

https://bitbucket.org/wuzzeb/notmuch-web

The server is written in Haskell and the client using Bootstrap and Jquery.
It should work on any HTML5 browser: I have tested it on Android and
desktop Firefox.  One feature of GHC (the haskell compiler) is the ability
to statically compile binaries which don't require haskell installed to
run, so I have built binaries for linux.  They only require glibc, libgmp,
and zlib.  I use these binaries to deploy from my desktop (where I develop
and build) to my server (which has no Haskell installed).

https://bitbucket.org/wuzzeb/notmuch-web/downloads/notmuch-web-0.1.0.i686.tar.gz
https://bitbucket.org/wuzzeb/notmuch-web/downloads/notmuch-web-0.1.0.x86_64.tar.gz

Configuration, instructions on building from source, and other information
are on the web page.

John