I'm thinking about doing this to promo awareness of an artist.

buying 500 aged accounts with at least 500 real followers.

Set each account to tweet every 50-60 seconds to different people in the particular genre of music niche. From 100 different proxies.
Example : Hey (twitter name here) have you checked out "Artist Name"

Then the twitter name swaps out for each message.

I figure I could tweet thousands of people about the artist name everyday and sense there's no link it wouldn't set off the twitter spam parameters.

Ideas on how this could be improved or any issues I would run into .

Hmmm.. to be honest I am not a big twitter marketer mostly because twitter is not very hot in my target country. However, in my relatively amateurish (and similar to your) approach to twitter marketing, I found that my posts seemed to go unnoticed most of the time..maybe I didn't try hard enough.

for artist awareness, I would play more on some free stuff, like free jingles for radios, or free idk.. anything.. people like free things, even from artists they have never heard of.