Hello and welcome!
A long, long time ago, all the way back in 2008, there was a guy named klingsor who made a beautiful 6541. It was very good, but also unfair, since he'd used a genuine case to build it. I don't believe there have been too many 6541 projects since then.
There was a small amount of buzz in December, when a new 6541 rep was introduced (alongside a somewhat disappointing 6542 GMT). The most obvious change from the previous 6541 was the addition of a new caseback and Faraday cage, and the midcase looks to be entirely different. However, I'm not aware of anyone who has bought this new rep, let alone reviewed it thoroughly, or compared it with the gen. Likewise, I don't know if anyone has evaluated the accuracy of the pricier cases available from Phong, Yuki, or NDT.
Might be a good place to start, especially at less than $200!