http://www.sparkfun.com/commerce/product_info.php?products_id=683

could be interesting but the spec sheet is blank.

in their description they say that it's a common cathode configuration,
that just means that all the negative ends of all the LEDs are grounded
you just solder to the positive side and give it 5V.  could be driven
from 3 max7221 LED drivers, not a complete drop in tweak for use with a
logic board, but it's an idea.

My (still very conceptual, but slightly in-progress) custom monome 
project involves three logic kits. I briefly considered using one of 
these as secondary eye candy, simultaneously displaying the LED state of 
the three kits, but ultimately decided against it, as it wouldn't 
actually be terribly interesting or informative under normal operating 
procedures.

u mean LED boards or logic boards?

Logic boards. My aim is to do something very different from the 40h in 
terms of I/O look and feel.

holy moley!!  so 3 USB ports?

i dunno if you noticed the dimensions of those things, but they're 
ridiculously small.

http://www.sparkfun.com/commerce/present.php?p=Tetris

scroll about 2/5 of the way down the page.

@revbean: sounds great, can't wait to see it. what are you going to do 
with the leftover button lines?

I believe those are different buttons, those are the silicon buttons 
that sparkfun copied from monome.  there's a pic somewhere on this site 
with both types next to each other and the sparkfun silicon buttons are 
about twice as large as the monome buttons (I have some.)

seems to me that the tri color matrix have opaque covers over the LEDs, 
there's no buttons on the thing.  I don't know if they're made to line 
up with the sparkfun silicon buttons.

it's hard to tell without a freaking spec sheet.

no no no, i wasn't talking about the sparkfun buttons. i've got a set of 
those as well. but, look 2/5 to half-way down the page, under the button 
control pcb picture..

or, for convenience:
http://www.sparkfun.com/commerce/images/Matrix-Serial-0.jpg

<slaps forehad>
thanks, nice catch!!

you're right, they're small.  it'd have to be a monome for toddlers, 
turn those kids into nerds at a young age.

@tone: I believe that the SparkFun part is from this line:

http://www.ligitek.com/search_group.php?groupID=GF

I'm sure I've seen a dtatasheet for a tri-colour matrix somewhere, but 
the Ligitek site is not the most user-friendly, and a in a quick perusal 
just now I only saw single- and dual-coloured.

From what I recall of a rather exhaustive search of a few months back, 
SparkFun are the only people who seem to be selling the tri-coloured 
matrices to a retail audience.

@tehn: My initial impulse was to use an 8x8 tri-colour led grid _in 
addition_ to whatever I/O I eventually settled upon. As a status 
indicator/extraneous pretty blinking lights, the buttons would be a 
separate matter. As my current design stands, I do have 16 buttons that 
I'm not sure exactly what to do with though.

These matrices would be awfully small to use as an input device. Plus, 
and more importantly, I have no idea how you would go about rigging 
buttons up on top of them. Although it would make a pretty cool, tiny 
little, pocket calculator-esque device. Hmm. Maybe I'll have to think 
more about this if a second round of kits is produced.

I'm still planning on building a secondary display grid into my box, but 
decided to go with an all red matrix, which is is available from Jameco 
in 5x8 blocks. (Part number 183265. I'm not an EE, but it seems to me 
that the datasheet for this one has the LEDs drawn in backwards.)