Is there any way to reference a subquery in a union?

I am trying to do something like the following, and would like to avoid a temporary table, but the subquery will be drawn from a much larger dataset so it makes sense to only do it once..

SELECT * FROM (SELECT * FROM ads WHERE state='FL' AND city='Maitland' AND page='home' ORDER BY RAND()) AS sq WHERE spot = 'full-banner' LIMIT 1
UNION
SELECT * FROM sq WHERE spot = 'leaderboard' LIMIT 1
UNION
SELECT * FROM sq WHERE spot = 'rectangle1' LIMIT 1
UNION
SELECT * FROM sq WHERE spot = 'rectangle2' LIMIT 1
.... etc,,

It's a shame that DISTINCT can't be specified for a single column of a result set.