From the link you show, the backport of Tomcat7 seems easy, indeed. And if all works well you should end up with a tomcat7 package that fulfills your requirements. But...
It might have worked back a year ago (when the blog post appeared) but now I think there is a catch. Actually, the step apt-get build-dep tomcat6 is a bit tricky. What should really be done is apt-get build-dep tomcat7. Once you try to do that, you'll see that the work is a bit more tedious. A few other packages will come up as build dependencies and you'll need to install them, if they are available, or build them from sources if not.
Build process
From my trials, I've find that to be able to build tomcat7for your users, you need to:
- enable squeeze-backports and install from there
maven-repo-helper and javahelper,
- build from wheezy sources
jakarta-taglibs-standard and install it on your build machine.
At the end, the whole procedure as I've done it looked like (version numbers provided as of 06/03/2013):
# adding wheezy sources to your apt config and preparing the build host:
echo "deb http://backports.debian.org/debian-backports squeeze-backports main" >> /etc/apt/sources.list
echo "deb-src http://ftp.debian.org/debian/ wheezy main" >> /etc/apt/sources.list
apt-get update
apt-get install dpkg-dev build-essential fakeroot
# manually adding missing build dependencies
apt-get -t squeeze-backports install javahelper maven-repo-helper
# getting the source package for jakarta-taglibs-standard, building and installing it on the build machine:
cd /usr/local/src/
apt-get -t wheezy source jakarta-taglibs-standard
apt-get build-dep jakarta-taglibs-standard
cd jakarta-taglibs-standard-1.1.2
dpkg-buildpackage -rfakeroot -b
cd ..
dpkg -i libjstl1.1-java_1.1.2-2_all.deb
dpkg -i libjakarta-taglibs-standard-java_1.1.2-2_all.deb
# getting the source package for tomcat7 and building it (this takes some time...)
apt-get -t wheezy source tomcat7
apt-get build-dep tomcat7
cd tomcat7-7.0.28
dpkg-buildpackage -rfakeroot -b
Peculiarity of tomcat7 7.0.28 source package
The listed instructions above should be all that's needed. However, there is an expired certificate in the tomcat7 7.0.28-4 source package in the Wheezy/testing repository (a self signed certificate expired on Feb 27th 2013). This will make the build failed in the unit tests.
There are 2 solutions to solve that:
Installation
As you've seen in your link, you will come with a few tomcat7-... packages that you'll need to provide for your users. The best would be through your own repository so they can install all that easily.
With all those packages, all should be ok and your users will actually have a backport of Tomcat 7 to Squeeze. If your users then migrate to Wheezy, they should have no issue as any new Tomcat 7 package in Wheezy will have a bigger version number than the one you've provided them. They'll receive the Wheezy upgrades just fine.
Maintenance
One last thing you need to consider are the Tomcat 7 security or bug fixes that comes into Wheezy later on. If a serious tomcat7 update pops up in Wheezy, you should really consider rebuilding your own tomcat7 packages and provide those same updates to your users.
