I doubt you're going to find large quantity soil-in-a-paper-bag, but you might be able to fashion the paper bag out of yard debris paper bags commonly found in bundles of five, and put the soil in that. Some landscape supply companies might let you purchase topsoil that you would scoop right into the paper bags. I would think the paper bags would get heavy in a hurry and tear easily, and once placed in the garden spot would fall apart from moisture.
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I'm getting way to old for these new gardening ideas! Plants in the ground. That's my story and I'm sticking to it.

Ok, paper bags was a silly idea. Of course they'll fall apart when they get wet! But I'm still going to try out the bag garden. I've just finished removing sod for an entire front yards worth of new flower borders and I'm dead sick of digging sod! :-) We'll see how it goes.

thesecretofjoy: why don't you lasagna garden on top of that previously sodded area? Takes a bit of time to gather materials to layer, then in pockets put compost + other soil for your transplants. We've not done seeds. Save that sod to compost & in 2 years you'll have fabulous soil.

layer ideas are basically what you'd put in compost bins:
-starbxxk's coffee grounds
-vacuum cleaner bag & floor sweepings
-household fruit & vegetable scraps
-household paper waste (kleenex, toilet paper rolls, napkins)
-office paper waste (shredded sheets)
-feed store sweepings (many feed stores have a dumpster where they collect the stuff swept from their bale storage, go ask & it's free - our experience has only been favorable as the seeds have fallen out already & ask you lift the debris from dumpster yet another chance for seeds to fall. Oats sprout & are easily pulled up & added to next layer.
-grass clippings (mix w/dry leaves, straw, etc. or lay down a very thin 1/4" scattered layer to avoid a stinky mess)
-composted horse manure mixed w/ bedding
-partially composted chicken, duck, and rabbit manure