I don't think a character should need quick draw or a magic weapon in order to use its multi-attack powers with thrown weapons, so long as sufficient ammunition is available.
Bingo.. and by RAW they dont.
Several options work and leave the players description about there arrow use up to them
1 is let the character purchase high balance 'trick shot' arrows that are effectively pulling out two when they go to do a multi attack. If people want there character to use these but dont do multi shot attacks .. explain they break less often so they are able to recover them more easily. You can also allow them to buy really cheap ones which break and splinter more often.
2 is not tracking arrows any more than you track the bat quano the warlock used in his last spell (you will find threads with support for this idea and I dont mind it because - for one thing I hate accounting = but I do know there are players who like the numbers and would be upset if we didnt dot the i's.)
3) house rule like klaus suggested and allow twin strike to cost one of the normal cost arrows but with some penalty on performance.
Remember realistic tracking of arrows may have your characters spending a good 5 minutes hunting in the grass per fired arrow .. so how many rest periods in a row are we taking this time mister ranger. (remember an arrow which delivers hit point damage did not necessarily get stuck in your target or deliver a gash or scratch.. it might have resulted in him dodging and straining a muscle or running a little more out of luck etc.. your arrow merrily diving into the folliage or breaking on the cace wall).
I suspect the player of the archer character will like the idea of purchasing more expensive arrows for his ranger.
I do like the house rule idea of allowing a pc using the normal arrows to spend some effort (reducing the quality of his attack in some fashion to reduce the ammo cost of his attacks .. it wouldnt have to be anything to do with trick shots or multi attacks... just paying more attention to where the sily things go after you fire would be enough of an excuse... it makes them easier to find afterwards).
when dungeon delving there less hunting and more cussing about the arrows being broke instead of lost.