Reddit mentions of Ultra Pro Postcard Soft Sleeves Ultra Clear | Holds 3-11/16" x 5-3/4" Postcards | 100-Count

Here's what I do: I put them in these first, and then slide these postcard sleeves over the top. The postcard sleeves fit perfectly over the top of the Ultra Pro oversized commander sleeves. There is a little overhang at the bottom which can be easily trimmed with a hobby knife if it bothers you. So it's sort of a reverse double sleeving, but just as protected nevertheless.

UltraPro makes postcard sleeves that are larger than oversized cards, but open on the short side and shuffle nicely. They are clear instead of having a colored/textured back so they look like penny sleeves. But they're cheap and work well. I got them after having the same complaint for my Planechase stuff, and commanders.
http://www.amazon.com/gp/product/B001A3BEW4/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Also for my planechase stuff, I had a shopkeeper suggest laminating them. Which really isn't a bad idea if you intend to keep things for a long time (and planes aren't super expensive, I don't think).

I don't have the DA tarot deck, but I have the DA playing cards and I have some of them in regular card sleeves stuck to the wall with poster tack. It's nice 'cause it lets me take 'em down and play with 'em sometimes, or swap out which ones I'm displaying fairly easily.

Is the DA deck bigger than poker cards? You can get odd sized playing card sleeves, but I've also used post card sleeves taped over or cut down for bigger decks.