if you level up while in que for a bg or your raf joins a que and you grant him levels he will be that level while in a bg so you can go to level 19 29 39 ect and make sure you just need 1 bar till lvl then you complete a quest and level then just go to trainer learn new spells and get your mount i did this in the 20-29 bg and i was the only one with the mount so i just ran as fast as i can and capped most of the flags
i searched for this and nothing came up this is my first post and i knew about this for a couple of years already just was to lazy to post it i havent tried it with the new join que from anywhere but i am sure it would work also