Is there any rules that spell out or can be applied to creating your own BTL chips as a player?

Anything can be done as BTL's, as long as you can get the emotive track. BTL's don't give bonuses or the like, only the addictive sensations

I'm not going for bonuses, I have a character that wants to create his own for recruitment purposes.

Check out the section on creating simsense in Unwired. It's pretty hard, looks like.