It's not enough that the big down-town stores have moved to the suburbs. Now they're moving Georgetown itself out to White Flint.

What has to be the first shopping center ever designed to look like another shopping center is taking shape on the top floor of the giant complex on Rockville Pike.

It's all there: the streetlights, a real hydrant, an actual manhole cover bought from Washington Gas Light, the brick paving. All that's missing is the moss and cigarette butts between the bricks.

So far only one shop, The Unendangered Species, which features gifts shaped like animals, is open, but eventually there will be 18, according to manager Walter Gold. Half the spaces are leased already, and by March the mall-within-a-mall should be almost half completed.

True, the streest signs aren't really facsimiles, and the names have been changed - Volta Alley, Dumbarton Court and so on - and the brick walls are mere facing to conform with the local building codes, and the whole little maze of streets is bit too scrubbed and pastel colored to pass for the real thing.But once the shops are open and the streets are all a-jostle with goggling shoppers licking ice cream cones, you'll hardly know you've moved.

And there are some nice funky details: here and there you discover what seems to be an actual George-town window frame with its flecked and peeling paint, its crumbling putty, evidently jimmied out of its original wall and implanted amidst the newness like a windshield from a 1947 Ford grafted onto a '78 model.

"The mall was going to be downstairs," Gold said, "but they decided to put the Via Rialto there, so George-town was moved to the third floor.We've got 17,000 square feet of leasable space."

Never mind the cute carriage lanterns and the benches and planters and other suburban fripperies - it's still about as close as you could get.

And it's driving the sociologists crazy.