Still haven't found what I am looking for, so lowering my level requirement. Now looking to buy a guild level 22 or higher. Lower can be discussed, but only when it's a very active guild with a lot of members. Achievements, number of members, etc. doesn't matter, but will obviously determine the price I will pay.
My aim is to start a new 10-man raiding guild, so I will not be kicking any members.
Prefer to pay in gold, but other options are possible.