You didn’t happen to notice if they had Bissell Style 4s did you? I’m finding them similarly elusive.
I dunno - my manual just says plain old “U”.
The vacuum is an upright. The bag is oblong in shape with the hole (that the bunny fur goes into) about 3/4 of the way down the back of the bag. The hole is about 2" accross and is reenforced with cardboard so it can slip over the plastic fur spraying nozzel on the inside of the vac.
What brand is your vacuum?
This might work out well. 
So, I got curious as to what bag my Dirt Devil uses. I have a Can-Vac, which is quite small, and lives in a big canvas tote, along with its attachments and extra bags. The tote was in the bedroom where my husband was sleeping last night. So I turned on my reading light, went rummaging around in the bag to find a package of vacuum bags, and jumped into bed. The husband turned over to find me perusing a package of vacuum bags in bed in the middle of the night. The look on his face: 
My response: “don’t ask.”
This message board makes you do weird things.
FWIW, I use Type F MicroFresh Bag For Can Vac/Power Pak
3 Bags + 1 Filter Combo Pak
Generally I find them about the same.
I actually bought my vac at Canadian Tire because it was cheaper - I should have known better - they didn’t have any “U” bags then either. (I checked so I could have extras on hand).
If you’re not looking for anything in particular then Canadian Tire is great - you’ll probably find something you want.
However, if you’re looking for a very specific item - a “U” bag for instance - then 9 times out of 10 you’re out of luck.
The staff are friendly enough, albiet elusive; however they can never seem to find anything either. They’ll search on the computer, say “Yep, we have em.” but then not a single employee can actually find what ever it is you’re looking for.
I’m gonna start phoning around to Walmarts and see if any of them might have a bag or two.
Confirmed sighting of Royal Dirt Devil U-type bags at Westbrook Walmart as of about 20 minutes ago.
ACK! Let me phone them right now!
Well. They’re holding a package for me.
Horray!
This really is absurd.
Well, if that doesn’t work out, let me know. I was rummaging through some stuff for spring cleaning, and lo and behold, I found two “U” bags! Whoo, I guess.
Personally, I think the terrorists are collecting “U” bags in a strange, sorted plot to prevent good people of the free world from vacuuming.
IF I CAN’T VACUUM, THE TERRORISTS HAVE ALREADY WON!
::ahem::
Honey, if you’ve had this much trouble finding the bags, buy 2 packages at Wal-Mart. As the person I used to be married would say “they don’t go bad.”
This is one of those moments when the power of this message board amazes me.
-lv
All hail the power of the board.
And Alice, congrats on being able to vacuum your carpets!
I don’t know whether to be amused or afraid, but at least I’d feel safe walking barefoot over Alice’s floors.
QUICK! Put them on Ebay…you may get $50 (US or C, would it matter??) for these prized bags!
And I looked…the elusive U bag described sounds just like the bag for my Panasonic vac. Pathetic Panasonic vac.
You guys are absolutely hysterical. I love you all. 
I wonder if the elusive bigfoot uses these elusive U bags? Maybe bigfoots (bigfeet?) around the world have been buying all the U bags and that’s why you can’t find them. Hmmm…
Jeez, I’d hate to see you guys during an Easter egg hunt…
Well now.
My roommate picked up “U” bags at the Walmart Gut mentioned.
I managed to find a single package at an exclusive vacuume repair shop.
My mom found 3 bags in Manitoba and is shipping them out tomorrow.
Cranky and I have bartered a nifty deal involving “U”-type bags and kinder eggs.
I have ordered a package of 10 U-bags from Dirt-Devil, on line. They’ll be here in 3 weeks.
I’m telling you - it’s either feast or famine in the ol’ vacuum biz.
::“U” bags, for all my friends!::
Uh, oh, the manic phase must be kicking in. Since reading this thread, my mind has been composing a new musical:
U Is The Only One
By Andy Berlin
I like to keep the carpet clean
So sparkling and pretty
It’s always clean with such a sheen
Not ever coarse or gritty.
I vacuum up so often that
I vacuumed up the kitty.
But now my days are full of tears
The sun is gone from view.
I’ve been to Kmart, been to Sears
But I’m still without U.
(Chorus)
Oh what is a girl to do, what in the world to do
When the onliest, onliest bag that will do
When the onliest bag is a U?
I went to the Italian grocery
I had no place else to go.
I said to them, “I need a U bag.”
They said “We needa you dough.”
Why can’t they understand my plight?
Why can’t they ever get it right?
I don’t need a G
I don’t need a T
Not an M nor an N
Surely not X, Y, Z.
They have got A, B, C
And a huge double D.
Oh, wait, that’s a bra.
Will that work? Let me see.
(Chorus)
Oh what is a girl to do, what in the world to do
When the onliest, onliest bag that will do
When the onliest bag is a U?