For anyone who's interested, here's the meaning behind my nick and the character design I had in mind, it should be pretty straightforward actually but I'm graphically challenged to say the least!
Name Origin
When I joined SL I had to use the surname "Numbers", which actually works well for me since I did a degree in math and physics. In mathematics, "cardinal" numbers are used to describe the size of sets, particularly various types of infinite sets for reasons which are important to the foundations of mathematics (for example, even though there are infinitely many integers, there are a lot more fractions, so you can define different cardinal numbers to describe the relative difference between the two sets).
Of course somone had already grabbed the name "Cardinal Numbers", so I went with "Kardinull", the "null" part representing the smallest possible set (an empty set), as well as being a standard computer programming construct, to reflect the Metaverse origins of SL (the K in Kardinull also being a hacker-ish touch).
Character Design
An obvious inspiration for the visual design would be a Catholic cardinal, both as a visual reinforcement of the nick and since cardinals are often thought of as mysterious figures commanding powerful secrets (like the foundations of mathematics!). A cardinal's outfit is quite straightforward, traditionally a simple red robe:
http://www.precious-times.eu/deluxe%20cardinal.jpg
For colour and texture I was thinking a deep red velvet, much like JP2's robes of state:
http://i.a.cnn.net/cnn/interactive/world/0504/gallery.vatican.events/05.pope.state.pool.jpg
However to reflect SL's modern setting, I was thinking of a much more modern tailoring job, something like the coat Neo wears in the Matrix 2 and 3:
http://tecnologia.tiscali.it/sfondi/matrix_reloaded/media/Neo_Matrix-reloaded.jpg
http://images.quizfarm.com/1130268505NEO.jpg
Other touches to the outfit could be a jacquard inlaid with various mathematical symbols, or perhaps just a simple aleph-null instead of a crucifix (aleph-null being the smallest transfinite cardinal representing the size of the set of counting numbers, e.g. 1, 2, 3 etc.):
http://www.tbray.org/ongoing/When/200x/2003/04/21/Aleph-Null.png
For the character himself, I was thinking he should be humanoid but just a bit extraterrestrial - think Dr. Manhattan from Watchmen:
http://www.fumettidicarta.it/Garage_Ermetico/DOSSIER%20WATCHMEN/watchmen10.jpg
http://fp.ignatz.plus.com/images/Manhattan%20LifeDeath%20small.png
I imagine it would be trivial to take an existing SL skin of a muscle-y dude and remove his hair, harden his facial features, smooth over his eyes and so forth, but again I'm graphically challenged so take that advice with a grain of salt.

Anyway thanks for reading, and if you have any suggestions or would be interested in working on such a design, feel free to post here or PM/email me, I hope to be gliding around in a much improved Kardinull Numbers avatar soon!
