Multiple Strain Gauge Recorder

I am looking to start a project for recording the readings of 20+ strain gauges at at least 1kHz (Arduinos run at 10Hz sample rate, but each port or individual?), Ideally it would be able to run off a battery pack. This is my first project with an Arduino, but I am fairly comfortable with programming. I however am totally unfamiliar with the hardware.

So far what I have come up with in the list of in the way of requirements is.

Ardunino Mega2560
SD Shield (Suggestions Appreciated)
Amplifier
Strain Gauges
Power Supply (Again Suggestions Appreciated)

Other concerns:

-How does one create/modify programs on the chip (Inserting Files over USB?)
-Access from Ubuntu environment, is problematic?
-Any specifics one should know about building a case for it?
-Canadian supplier

Any help would be appreciated. I have done some preliminary research, any any good guide referred will be read in depth.

Thank you for your time.

I am looking to start a project for recording the readings of 20+ strain gauges

So, first thing to do is to select an Arduino with 20 analog pins. Good luck with that.

Is there anyway to digitalize the data perhaps with a secondary controller and send the excess on? So you have 2-3 chips

1 that writes the data
1-2 that reads the data and digitalizes it

You might want to visit the multiplexing discussion area.