Can an admin get this info?

Chronos > Gladiator > Orc

^ Three most popular force colours.

This isn't a joke, they are the three most commonly bought and sold forces.

Lol. Well lets suppose I were to recolor a set, what would people be most attracted to buy? I've seen lots of people with elf recently, so maybe make it purple?

A list of the most popular force colors isn't going to help you sell a set. Those cheap forces like orc/chronos are probably the most popular but they are also worn by kids that can't afford a texture set most of the time.

I'd make the set orc, gladiator, or chronos.

Elf Requires - 15k qi. Not such a common force...

http://forum.toribash.com/tori_shop.php?cid=22
Go there^
Check number of forces owned by people
Find the most owned
Make set
Don't profit because availability/affordability of an item isn't an indicator of its popularity

What you need is simply market knowledge. Best advice I can give is to go ingame and hang around with people who have enough money to be in the market for your set and see what they wear.
Greyscale stuff is always popular and is popular mixed with strong base colors like Toxic, Static, Vampire, Elf etc...

Tell them you will do a free recolor, and then just adjust it to match what they ask for.

That way you can charge more, do less work, and have a larger potential customer base.