Wow, am loving this thread even though we're getting way off topic. OK, here's 2 methods I'm toying with, based on "What's the least amount of changes I need to make to my cube memo system to measure cards, whilst being efficient".
For the record, I use letter pairs in SVO, (Adam Ant Arches Around an Armoured Armadillo / Billy Bunter Brick-Builds Ball Bearings), so it's six-letters per image. Now, bear with me. This is how I try to encode 5 cards in 6 images.
Classify all suits as "Blunt" or "Pointy". Clubs and Hearts are "Blunt", Diamonds and Spades are "Pointy". Now encode:
A=Ace of blunt. B=2 of blunt. C=3 of blunt.... M=King of Blunt, N=Ace of Pointy, O=2 of Pointy ... Z=King of Pointy.
Encode 5 cards in your image. Then convert the colours to binary, Black=0 Red=1. Convert to a number (0-31) and encode this as your last letter (Yes, I know I only have 26 letters. Hold on). Encode that as an image. Stick it in a location. Do this 10 times (with 2 cards left over), you've memoed the deck. Takes about the same amount of "space" as 3 cubes if done this way
Worked example (Apologies in advance if I make any mistakes):
3-Diamonds, 10-Spades, 8-Clubs, Q-Hearts, 3-Spades
3D = Sharp, Letter P
10S = Sharp, Letter W
8C = Blunt, Letter H
QH = Blunt, Letter L
3S = Sharp, Letter P
Colors, Red, Black, Black, Red, Black = 10010 = 18 = R
MEMO: PWHLPR = Paul Whitehouse HeaLs (like a healer in world of warcraft) a plate of Pickled Radish
DISCLAIMER: I can't yet actually do this!

~ The good news is to get fast, I just need to "rote-learn" about 83 things (Card/letter association, and binary encoding of suits), rather than 2704 brand new images. If I can, then speed cards may be fun.
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Second method not thought through yet or practiced seriously:
C=Blue, D=Green, H=Red, S=Yellow (Blues Club, Green with Envy of diamonds, Red Heart, It's Yellow to call someone a Spade)
Ace = A, 2 = B ... 10 = T (T for Ten), Jack=J, Queen=Q or R, King=K. Do a similar image, but colour each object with it's suit (the top half with the first colour, the second half with the second colour). NB, Queen is Q or R because Q words are a nasty to come up with
Sounds ridiculous, but the memo seems to work. You really need to visualise your picture though, with the colours.
3-Diamonds, 10-Spades, 8-Clubs, Q-Hearts, 3-Spades, A-Hearts
3D = C, Green
10S = T, Yellow
8C = H, Blue
QH = R, Red
3S = C, Yellow
AH = A, Red
Memo = CTHRCA
Charlize Theron (Green skin, yellow clothes) HuRdles (Her pants are blue, her shoes are red) over a Candy Apple (yellow top, red stick)
Six cards per image. Tough and probably #fail.
Again, I've not actually succeeded in memoing a deck yet. Apologies for mistakes. Remember, my goal is "Come up with a way of memoing cards with as little extra work as possible". Thanks you all for your feedback above!