I hate to say this but this method isnt going to work HALF as well as you will expect.
Firstly, as soon as a few people realise your app is loading up a url its going to get flagged FAST, once it gets flagged it gets deleted. 1000 peers? NO CHANCE! you will be lucky to get 100. Now this is to say that your torrent even sticks in the first place, have you tried uploading to mininova or piratebay lately? If your uploading 'popular' apps they are going to get banned before they even get a single download, trust me i've been doing this for a long time and popular apps are so saturated that mods are just banning them left right and centre.
This idea has potential but its not going to get you anywhere near as much traffic as you think. The conversion rate for this kind of thing is awful aswell, im sure there are ways you can make this method work but you really need to think outside the box.
just my 2 cents, but even so thanks to the OP for suggesting it