If you want a mint Klein, you could also do what I have done?
I purchased an attitude frame MC2 off of this forum (not rigid unfortunately) and have sent it to EToE to be sprayed. Whilst waiting for it to come back I have sourced pretty much all the parts and will build it up once it is back. I know it won't be problem free to build it, bottom bracket and headset etc, but once it is complete it will be exactly as I want it.
You could also make the build more interesting, I set out on a non Shimano mindset, and have stuck to that. With Shimano it would have been easy just M900 which is readily available, but non Shimano has been more expensive and troublesome sourcing decent NOS or very clean parts over the past few months but has been a challenge and good fun - hopefully rewarding once it is built up and I am riding it