What about a set of handmade ceramic mugs? I don't think that would be blah at all, no matter how they are packaged! There are probably some places you could buy a set locally...think an arts center with a ceramics area, a college with an arts program, or a small art gallery. There are also a lot of amazing potters on Etsy. Here are just three stores of many that I personally think have beautiful mugs: Dawn Dishaw Ceramics, Metamorphoses Of Clay, and Julia Paul Pottery. I hope you find this helpful even though it's not exactly what you asked.

Hi, Crate and Barrel has a ton of options and I'll bet you could pick four and have them packaged/wrapped together: http://www.crateandbarrel.com/search.aspx?query=mug
The Merimekko ones are gorgeous!

I like the idea of Etsy too but getting something handmade and having it shipped may take more time than you have if you need to get it by Christmas.

I would do a gift basket with mugs and tea/coffee/cookies. You can go to Michaels and get baskets, filling and plastic wrap for the outside. I've done that type of thing with Starbucks mugs before.

I just recieved a Nespresso maker and the Bodum Pavina Double Walled Glasses.
While they are not packaged beautifully, they LOOK beautiful when you make an espresso or latte in them.
http://www.surlatable.com/product/PRO-172747/Bodum-Pavina-Double-Walled-Glasses

I was given a set of lovely Rosanna mugs and matching plates for graduation. They came in sweet boxes that match the theme of the dishes, which I still have stacked on a side table because they're so pretty. The only conceivable downside is that many of the products are porcelain (thought not all!), and microwaving/dishwasher use is "not recommended."

I should amend my previous comment, it looks like quite a few of the Rosanna mug sets are both microwave and dishwasher safe!

My dad got me a set of these Kate Spade mugs in college and I still use the hat box they came in. I LOVE it. I highly suggest it as a gift!

I like all the ideas above especially the clearer mugs but let me ask, does your Mom need another set of mugs? I'm sure she'll love them because they came from you, but we gather so many mugs you might want to re-think this idea.
I'm not a coffee drinker but can you buy accessories to go with the coffee maker or maybe some high end coffee grounds might work best?
Whatever you decide, best of luck.

Tom is having the same problem we all encounter with our parents,especially if they are older! What DO you get someone who has a houseful of literally everything imaginable? I agree with Lyonstill,perhaps some flavored coffees or some lovely little nibbles might be the way to go.Besides,dont we all have tons of cups in our cabinets,and dont we all have one or two that we use most?

Had you checked World Market?
http://www.worldmarket.com/category/kitchen-entertaining/drinkware/coffee-mugs-teacups.do

They have quite a few sets of 4-6 mugs in various non-holiday themes to choose from. Can't speak for the packaging angle, but a basket from the same location would solve the issue.

those rosanna mugs are gorgeous and sounds like it's exactly what you're looking for...

Maybe try something that really complements your mum's Nespresso. A gift of the capsules, or some of the beautiful racks that display them would be very nice. I have owned a Nespresso for some time, and use the Bodum glasses exclusively. Check out the Nespresso site for accessories, or if you have a Sur La Table in your town, visit them. Mugs? Meh.

Overstock has lots of mug sets. If the box they come in isn't suitable you could always just make your own: http://www.overstock.com/Home-Garden/Mugs/20294/subcat.html

Here are a couple I particularly like:
http://www.overstock.com/Home-Garden/Mikasa-Color-Studio-Turquoise-and-Platinum-Zigzag-Mugs-Set-of-4/6045590/product.html

http://www.overstock.com/Home-Garden/Red-Vanilla-Tuscan-Villa-Mugs-Set-of-4/6077768/product.html

I am a mom (though, not your mom). I, too, have an espresso maker, a gift from my son. What I want is these Iittala Taika Espresso Cups.

http://www.amazon.com/iittala-TAI500501-Taika-Blue-Espresso/dp/B001HJNXS4/ref=sr_1_16?ie=UTF8&qid=1354919871&sr=8-16&keywords=iittala+taika+cups

They come in other colors, too, and with or without saucers.

I don't know how they are packaged, but the cups will last for a long time, while the packaging lasts only a moment. Plus fancy packaging just means the hassle of recycling it somehow or throwing it away.

Packaging is easy -- you can find lots of pretty gift boxes in Home Goods and other gift-oriented shops these days, and put anything that fits inside with a bunch of crushed tissue paper and voila! So don't feel compelled to get only something "presentation ready". That tends to bring the price up more than is justified.

On the other hand, unless you are pretty confident your mother really would prefer new mugs or cups, I'm one of those who suggests geting the consumables instead. A variety pack of unusual flavors of coffee that maybe she wouldn't get for the machine on her own, for instance. Or some accessories, like really good biscotti or other cofee-compatible snacks.

I'm a mom/grandmother aged person, and my mug cupboard is full. I could get rid of some if prettier ones came along, but I have the ones I do because they go with my dishes, were gifts, are special to me, or are especially pretty, so making more space would be a chore. So, if it were me -- and, of course, it isn't, so your mileage may vary -- more mugs, no matter how pretty, wouldn't be as welcome as something to consume or offer guests.

While most people do have a lot of mugs, I can see getting a nice set as a gift --who wouldn't love an excuse to get rid of their mismatched, souvenir mugs for a set that is actually nice and fun to serve guests with? I'd love to get rid of my gradually accumulated collection -they're all different shapes, don't stack well or fit in the cabinet well and I can't say there is one I really love.

There are several sets on sale here:
http://www.hautelook.com/event/25357