Running a vented and a sealed enclosure!

thats a very good idea!  but it goes back to your original problem of not having enough air space for 2 in a ported enclosure.  if you havent downloaded winisd you need to, it will help you 'visualize' your choice.  i believe the web site is www.linearteam.org .  download the winisd proalpha version, its free.  your sub isnt in the database of the program so youll have to input the parameters, but once you do that you can experiment with your options before you build.  if you have problems with winisd post your sub specs here and maybe me or one of the other guys can help you plot the freq response of your box choices and figure out which way suits your needs best.