It IS possible!!

I cracked it! It is possible to have a 9x9 grid in which each of the combinations A1-I9 appear only once and the numbers (1-9) and the characters (A-I) appear only once in each row, column and 3x3 square like in a sudoku.
Below is the first solution I came up with, I used excel to make sure that I didn't have any duplicates and that I hadn't failed to make it follow the rules. I worked on the easiest sudoku I could find - one where no numbers have been put in yet!
You should be able to see how I filled this in - I can't believe it took me this long to figure out that this was the best way to do it! Pah.

A1 B2 C3 D7 E8 F9 G4 H5 I6
D4 E5 F6 G1 H2 I3 A7 B8 C9
G7 H8 I9 A4 B5 C6 D1 E2 F3
B3 C1 A2 E9 F7 D8 H6 I4 G5
E6 F4 D5 H3 I1 G2 B9 C7 A8
H9 I7 G8 B6 C4 A5 E3 F1 D2
C2 A3 B1 F8 D9 E7 I5 G6 H4
F5 D6 E4 I2 G3 H1 C8 A9 B7
I8 G9 H7 C5 A6 B4 F2 D3 E1

Is it possible?

I am considering knitting the "sudoku" blanket. This is made up of 9 colours and 9 patterns. There is one of each pattern in each colour.
Now the maker of the pattern claims that it is not possible to have both the 9 colours in a sudoku pattern AND the 9 patterns in a sudoku pattern.
I am not sure whether to just believe this, or to spend lots of time trying to prove it one way or another.
If anyone knows why - and can show me proof - this doesn't work, let me know.

Until then I'll be working on my complicated sudoku!