Template file bar.jinja:

{% for k, v in site.quux.items() %}
{{ k }}
{{ v.garply }}
{% endfor %}

State file bar.sls:

/tmp/bar:
  file.managed:
    - user: root
    - group: root
    - mode: 644
    - source: salt://bar.jinja
    - template: jinja
    - context:
        site:
          quux:
            blurfl:
              garply: |
                corge
                wibble
                wobble

State file baz.sls:

{% import_yaml "baz.yaml" as site %}
/tmp/baz:
  file.managed:
    - user: root
    - group: root
    - mode: 644
    - source: salt://bar.jinja
    - template: jinja
    - context:
        site: {{ site }}

And imitation pillar data baz.yaml:

quux:
  blurfl:
    garply: |
      corge
      wibble
      wobble

So let's run these two states:

[root@l-tsmsalt-101 states]# salt '*salt*' state.sls bar
[root@l-tsmsalt-101 states]# salt '*salt*' state.sls baz

And compare output.

[root@l-tsmsalt-101 states]# diff -u /tmp/bar /tmp/baz
--- /tmp/bar    2016-01-27 23:16:01.839356994 +0000
+++ /tmp/baz    2016-01-27 23:16:10.282133493 +0000
@@ -1,7 +1,4 @@

 blurfl
-corge
-wibble
-wobble
-
+corge\nwibble\nwobble

It looks like it makes a rather large difference how the variable site is passed into the template. Since import_yaml is a Salt thing, and not a Jinja thing, I'm wondering if the newlines are getting mangled there.

I'm trying to take advantage of the public apache-formula. It encourages you to store information about all your sites in the pillar (thus "imitation pillar data" above). It allows arbitrary bits of config to be passed as multi-line scalars, for when the provided templates don't do what you want. Look for Formula_Append. I'm not interested in Salting every possible bit of Apache configuration syntax when I only need to use this feature occasionally. Only 3 sites out of several dozen need it, and only for about 4 short lines at a time.

About the machine where my tests were run:

[root@l-tsmsalt-101 states]# uname -a
Linux l-tsmsalt-101.bhyve.local 2.6.32-573.7.1.el6.x86_64 #1 SMP Tue Sep 22 22:00:00 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
[root@l-tsmsalt-101 states]# cat /etc/centos-release
CentOS release 6.7 (Final)
[root@l-tsmsalt-101 states]# cat /etc/system-release-cpe
cpe:/o:centos:linux:6:GA
[root@l-tsmsalt-101 states]# salt --version
salt 2015.8.3 (Beryllium)
[root@l-tsmsalt-101 states]# python --version
Python 2.6.6

Salt was installed via salt-bootstrap on 19 January 2016, if that helps any.