I was in fact planning on writing those scripts for myself already. I guess some simple UI frontend and a proper package would be in order.

As far as BT tethering goes 1. you need to do some scripting for that too (also planning on seeing if those could be packaged nicely) ATM 2. wifi should be faster even if will eat more power.

EDIT:

Any new people should start reading from N900 as a Wifi Hotspot, part 2 -thread.