Need advice on a MIDI-to-light project with WS2801 strips and DMX support

Hello good folks, I am trying, like so many others, to build a light fixture for a band.

Here is a basic sketch of the setup: Imgur: The magic of the Internet

What I have so far is an Arduino Uno, an Ethernet and a DMX shield, 8 WS2801 based LED strands (200 LEDs altogether), ATX power supply.

I have also implemented a small custom Java application that takes the MIDI output from my sequencer (through the virtual MIDI driver) and converts it into signals to send to the Arduino.

What I am struggling with mostly is the actual connection to the Arduino. I would like to have a refresh rate of 20-25 fps. This means, at 200 LEDs, that I have to transfer ~15kB per second from my PC to the Arduino. So far neither the Serial connection over USB nor the Ethernet connection (using UDP) have been up to the task.

Another problem I am experiencing is the voltage drop over the total of the LED strips. They are after all over 10m altogether and when I set them to full on, the white turns into more of a red due to insufficient current.

What I am looking for is general advice on how to approach a project such as this. I know it has been done before (over and over), maybe someone could point me towards a couple of helpful resources (I've been over lots of forums). I would also appreciate help on the specific problems that I am encountering.

These are the strips I am using: 12mm Diffused Thin Digital RGB LED Pixels (Strand of 25) [WS2801] : ID 322 : $39.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Here is a similar project: http://www.solderlab.de/index.php/downloads/category/4-glediator

Thanks