I was considering buying a condo, in a building where 6 out of the 8 units are bank owned. How would i form a condo association

It sounds like you and the bank will be on the board. Normally a developer who builds condo project becomes the "declarant" and starts out as a one member association, and as units sell the control of the developer become incrementally less. In short, you will be the small government that runs the unit until new owners come along.
Make sure you have a complet accounting of the association finances and leins on the unit and association, in other words read the exceptions on the title report and if you do not completely understand the title report, hire a lawyer who can explain everything before you close.

I have pasted a link to the baseline law that will help you understand the system
http://apps.leg.wa.gov/rcw/default.aspx?cite=64.34