bro..i'm reading this post 2-3 times..and I'm not quite sure what you want from this chick.
You don't want the LJBF and you don't want to date this chick?
You want to "hang-out" keeping some sexual tension without the friendship or the dating?
The only thing this sounds like is that you want her in FB mode. Sounds a little ambiguous.
IMO..to get sexual tension...you need to date her initially. You can't just build sexual tension out of the air. You're going to have to date her. Go out with her. Do all the things you plan on doing with a ONS or STR. Kino, C/F, etc.
The trick here is that you're going need an 'OUT'. An 'OUT', meaning that you need a way to get out of the LJBF zone and the Relationship zone. But KNOW THIS...you can ONLY use this 'OUT' AFTER you have slept with her.
For FBs, my out has always been one of two things.
1) I just got out of a serious relationship. I don't want you to think I'm some kind of jerk that sleeps around. I think you're sexxy as hell. But, I don't see myself in a relationship...well, at least not right now"
2) I dont want you to think I'm some kind of jerk that sleeps around, but, I just got accepted to Dental School/Med School/College 100 miles away. I think you're sexxy as hell. But I don't see myself in a relationship...well, at least not right now"
End either convo with a kiss...and on a GOOD note.
She knows where you stand, the sexual tension is built, and you stay away from both the LJBF zone and relationship zone.
Also...by adding "well, at least not right now"...you give her something to hope for in the future, and that keeps you out of the LJBF zone because she knows your intentions aren't just friendly.
Just remember, you can only use the 'OUT' after you have slept with her. Try using this out before any sexual tension has developed, and you'll be in the LJBF zone faster that you can spell L.J.B.F.