I do not think seeed's has one


http://www.seeedstudio.com/depot/sd-card-shield-for-arduino-v21-p-492.html?cPath=104_109

http://www.ladyada.net/make/logshield/rtc.html

from adafruit

You can get going quickly - saving data to files on any FAT16 or FAT32 formatted SD card, to be read by any plotting, spreadsheet or analysis program. We even have a tutorial on how to use two free software programs to plot your data
The included Real Time Clock timestamps all your data with the current time, so that you know precisely what happened when

still learning my self but here are some things I reference often and from those and hanging around you can pick up on some other stuffs.

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?board=news

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1247637768

http://www.adafruit.com/index.php?main_page=tutorials

You can skip the official version of the board and get one from china as well as buy most of the components and still remain under budget for an original board.

If I was trying to build the space shuttle I would probably not go with components off ebay.

If I am getting parts  for me just to make some LED's blink the ease of them comming to my door at an inexpesive cost is actually pretty cool even if it takes a couple of weeks. 8-)

The easiest for you to use.

We do not know your skill level with either system so I would recomend to start with the one you know the best and work up from there with a working example and code.

That would depend on the "pen" that you use.

You can not implement a way to control something with an understanding of what you are trying to control.

If you use an injet head I would just send it the byte it needs to write that line on the media.

If you use a pen on a solonoid I would just send it the bit to either turn it on or off.

If you used a laser you would have a whole other set of problems.

Then depending on how large your media is it may be easier to move the media than to move your "pen" or Print head.

Is this going to be inkjet cartridge driven I assume?

There are several examples of arduino controlled inkjet printers on youtube.

If you just want to "print" something dump a string to port 9100. If it has to be a picture dump a PCL or Postscript file from a data shield to port 9100.

A heavy duty finshing line mostly secured to jugs used to fish for catfish.

That way when a big fish comes you can have a siren on the bank to let you know you have a big one!

trot line alarm!

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1277653199/8

he did a pretty impressive job for wanting to monitor his battery voltage.

Maybe take your multimeter to the local sewing/cloth/craft store and start checking the metalic type threads and such they have available.

At the shop I use I have just asked the person that works there and she pointed me right at the island and type I was looking for.