in xsl 1.1 draft (and xsl2 draft which is implemented in saxon 8) then
you can do just as you suggest

<xsl:variable name="something">
 ... xsl code ..
</xsl:variable>

then
select="$something/*"

(note that $something is always a root node / soto select the top level
element (or elements) that you create in the variable you need to
use a path such as $something/*

Cheers,
Wendell