Vegetables Gardening - Growing Organic Vegetables

Hello everyone!   I want to expand my garden and start using the Mittleider method this year.  I have some raised box beds made from 2x10 boards, but I'd like to try making some beds using cinderblocks.  I've priced them and it looks like they will cost about half what it cost me to make the wooden boxes, if I make them just 1 course tall.  But I have several obstacles to overcome.  #1: would a single course (making the box 8" tall) be enough?  #2: I am plagued with quack grass and bindweed.  #3: the only area on my property that receives enough sun to be a decent site is also directly over the leach field for our septic tank. (That's why I have raised beds - hoping it would lift the plants further away from the potential nasties - so far we haven't gotten sick from eating anything I've grown there).  Since the site sits over the leach field, and I have quack grass and bindweed, tilling the soil is not a good idea; but I need to get rid of these weeds.  With my original beds, I scraped what I could of the weeds, than added soil.  Bad idea.  I've been fighting the weeds ever since.  The next two beds got a thick layer of newspaper, followed by pine needles (we have LOTS).  That mostly worked, but I'm seeing them crop up again.  I'm wondering if I should buy some of that weed barrier fabric?  But will that stunt the root growth of my garden goodies?  Would it be better to go for a deeper garden box in that case?  HELP!  Spring is coming and my hands are itching to get at it!