After some research, as extensive as possible solely online, and aided by [thefind.com][1], I settled on these sets (click to go to the online store):

<a href="http://www.thechesspiece.com/proddetail.asp?prod=G-5LQ-DRW"><img src="http://www.thechesspiece.com/chesssets/magnetictravelopen600.jpg" width="256"></a>

<a href="http://www.thechesspiece.com/proddetail.asp?prod=Mag612"><img src="http://www.thechesspiece.com/indian/magnetic612/travel_chess_setS600.jpg" width="256"></a>

Both are magnetic, and are alleged to have strong magnets.

The first is a mere 7.5" board, but it doesn't fold (which I like), and it has a drawer (meaning that I can set up and tear down without pouring pieces all over the place or even move the board).  The price: $29.99.

I went for size with the other: a folding board, since the price was much lower for a folding board of that size (12") than for a board with a drawer.  This one costs $39.99.  

They have a claimed retail price of $79.99 each, which seems a bit exaggerated to me after seeing other stores' prices for similar sets.  I would place the value around $50 for each based on other prices.

I considered buying their [12" drawer set][2] ($79.00) in lieu of both the above, but decided against it, since it would end up costing more, and at this point I would rather have two sets.

Another set I was seriously considering is sold by another store.

<a href="http://www.houseofchessstore.com/magnetic_travel_chess_set_board_inside86teak.html"><img src="http://www.houseofchessstore.com/image/8x6-mag-brd-inside4_sm.jpg" width="256"></a>

I like this idea, since not only does it have a handy place for captured pieces to go, it also can be closed up in a certain position to be played later.

I'll update later on how the ones I purchased turn out.


  [1]: http://www.thefind.com/search?query=magnetic%20chess%20set#filter%5Bsortby%5D=price_asc&local=0&price=1-$100000&page=7
  [2]: http://www.thechesspiece.com/proddetail.asp?prod=12MAGSQ1