Question: Is it possible to show Post Thread button anywhere else, except forum home page?
Answer: Yes, it is possible by editing the templates directly or using Template Modifications, add the following code to any template where you need the button:
HTML:
<xen:if is="{$xenOptions.alqt_post_thread_button}">
<xen:topctrl>
<a href="{xen:link misc/new-thread-popup}" class="callToAction OverlayTrigger" data-cacheOverlay="true" ><span>{xen:phrase alqt_post_thread}...</span></a>
</xen:topctrl>
</xen:if>