Which clients interest you the most? 
Most web clients either already support it, or are trivial to implement with nostr-login or window.nostr.js
Native clients are mostly disinterested and I haven't seen any enthusiasm from them, unfortunately. 

 zap.stream definitely. All the good web clients would benefit from this hugely as it opens up web client use on mobile. I know Firefox has an extension but Firefox is a niche browser.  

 @Kieran I will zap you 500k if zap.stream gets nip46 support by the end of April 

Anyone else want to pledge? 

 Thats too much 

 It is not. Your work is awesome. 

 Not too much if it works 

 I'll add 100k. Bit poor atm.  

 Actually, make it 250k 

 That's getting serious 

 😂 yes. I also want you to pay @Kieran 👍 

 Well for that to happen you should persuade him to implement nip46 on zap.stream