Kanye West's Marriage Proposal -- Coming to a Kardashian Show Near You

Kanye West pulled out all the stops when he proposed to Kim Kardashian last night ... paying the orchestra members a relative fortune ... all while cameras were rolling.

A member of the orchestra tells TMZ ... she was paid 4 times what she usually gets for such a gig -- members snagged up to 1k each.

She says no one got wind of Kanye's plan until 2 days before the event. A contractor reached out to a bunch of musicians in the area. But here's the thing ...The orchestra members kept the secret for a full 2 days. They did sign non-disclosure agreements, but you know how that works ...

The woman also tells us ... multiple cameras were rolling during Kanye's proposal, so there's plenty of material for the Kardashian reality show. We're told Kanye has final approval over whether it goes on the show or not.