Ready :-)
Stripe is a service I'd love to use, however I'm not yet at a stage(small revenues) where it would be worth bothering you to be part of the 'closed beta'.
With regard to timeframes -- it really depends on what we discover during the beta. There are no major, obvious blockers right now, though.
I ask this as an Israeli that would love to have a good service, but seeing as we're a tiny country I doubt we're high up on the list :)
Perhaps we should all use the title "UK beta" to help you filter them.
(sorry, if it states that in the TC article...but I don't click TC articles)