As you discovered, there are some things required by JBoss Tools which must be sourced from the internet - they're not included in the update site. We don't re-distribute org.eclipse.* stuff, but we DO mirror it as part of our target platform provisioning.
Thus, the TP used by JBoss Tools 4.1.0.Beta1 (and JBoss Developer Studio 7.0.0.Beta1, too) contains both httpclient and httpclient4, as that's what's in the matching Kepler site from which we mirrored.
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If you want a completely offline way to get JBoss Tools, try JBoss Developer Studio, which ships as an installer jar. That jar (which can also be used as an update site), allows two ways to install JBT without needing an internet connection.
The latest JBDS 7 is here:
https://devstudio.jboss.com/earlyaccess/7.0/