How can we describe "gigabyte" in kanji?

Basically, kanji is used for Japanese (Chinese) words and katakana is used for words coming from foreign countries.

But there are some kanji for katakana words.

米 means “meter”
千 means “one thousand”
毛 means “small, thin”

米 (me-toru) “meter”
米＋千＝粁 (kiro me-toru) “kilometer”
米＋毛＝粍 (miri me-toru) “millimeter”

瓦 means “gram”

瓦 (gramu) “gram”
瓦＋千＝瓩 (kiro guramu) “kilogram"
瓦＋毛＝瓱 (miri gramu) “milligram"

We usually use katakana but kanji for the above words, but it’s still interesting that there are some knaji which we can’t describe in Japanese words.
Don’t you think so?
I’m not sure if these kanji is used in Chinese too and if they pronounce same way though.

Well, maybe we can “develop” new kanji for some English words.
How about some words used for computer?
Do you have any idea about kanji for “byte” “mega” and “giga”? ;)


Note:
To type the above kanji, I used Windows "IME Pad Hand writing".
http://www.microsoft.com/globaldev/handson/user/IME_Paper.mspx
Those are not 常用漢字(jooyoo kanji) which is basic 1954kanji we lean in elementary school and junior high school in Japan.