Zingerman's mail order sells back bacon:

http://www.zingermans.com/Product.aspx?ProductID=M-IRI

Not terribly cheap. I'm also married to an expat, and keep meaning to order some for him (though he prefers unsmoked back rashers, which are outright impossible to find).

Occasionally, Irish butchers have imported Irish back bacon as well, which is similar.

Get Canadian bacon (back bacon) instead. It's lean and taste good.

Check out Spencer's Jolly Posh Foods. They are based in Chicago and offer online ordering. Their back bacon is very tasty. http://spencerfoods.com/

Canadian bacon is not the same thing as British back bacon. Although both are cut from the loin, the Canadian bacon is cut and cured differently and is much leaner, lacking the fat and "tail" of British or Irish back bacon. Moreover, what's sold as Canadian bacon in this country isn't very good (or, apparently, much like what's sold in Canada!)

try for "Irish" bacon instead? my local stores carry it.

Seconding the Irish bacon suggestion. I've yet to find a perfect piece of back bacon, but the Irish is close as it at least keeps the fat. The Canadian stuff tastes more like ham to me.

Try contacting a community sustainable agriculture in your area. Mine has pork shares available and sells extra "shoulder bacon" separately by the pound after pork shares come in.

The fat lady hasn't sung on Fresh & Easy yet, there has been no decision yet to whether or not they are completely shutting the chain down. So keep shopping there in the meantime.

@LMCummings I know it hasn't closed yet, and I keep shopping and stocking my freezer with the bacon, but I am preparing for the worst! It is the only British food product that my husband misses on a regular basis!

British bacon is a wonderful thing - and it's much easier to make your own than you think. You just need to marinade some pork loin in the cure, and store it in the fridge - I blogged about it last year http://adventureswiththepig.wordpress.com/tag/back-bacon/

I know it sounds like a lot of hassle, but it's actually really simple, and totally delicious!

How interesting -- back bacon was about the only thing I didn't like while living in London. I miss the ubiquity of boxed sandwiches, however.

You might try Myers of Keswick: http://www.myersofkeswick.com/

Oddly enough my small town, Southern Californian Asian market sells British bacon and many other import items from the UK. I believe the owners are originally from Hong Kong, so there is a bit of a colonial connection, but it might be worth a shot if Fresh and Easy does close.

I found this, surprisingly, at a Stop and Shop in Parsippany, NJ. I bought a pack immediately.
Funny story, when I was in Scotland, I loved this bacon and bought a package and brought it back to the US. When customs asked me if I had any food, I told them exactly what I had, and he let me go through. I've heard since that any meats, including tinned ones, have been confiscated. Go figure.

I would also say look for rashers. Food Ireland has Irish rashers/back bacon
http://www.foodireland.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=spi202&Category_Code=breakfast&Product_Count=4

I'm from Ireland and really missed the rashers from back home. In Canada (where I live now) you can get Wiltshire bacon rashers at any superstore / Loblaws - it is the in-house President's Choice Brand - I'm not sure if it's sold in the U.S. though.

Tommy Moloney's sells back bacon if you don't mind it being shipped. I live in an area where i'm lucky if I can find bangers and forget any puddings. Unfortunately I can't bring anything back across with me from Canada.

Proper British Bacon & Meats in Auburn, WA makes it, both smoked and unsmoked. They carry quite a bit of authentic British food in their shop. You can order online at Proper British Bacon

If you're anywhere close to NY, I know that Myers of Keswick will have it. http://www.myersofkeswick.com/

I recommend Baker's Bacon. It's not super cheap, but a good value for the quality.
http://www.bakersbacon.com/