I don't know if 50BTC is the fixed amount to become a VIP member maybe try asking theymos about it.
Condition to become a VIP member did not change. 50
BTC is the condition.
Some exceptions for people with very big contributions to the forum, without 50
BTC in donation, can be awarded a VIP badge.
I gave Hal a VIP tag even though he didn't donate because he is nearly as much of a Bitcoin legend as Satoshi IMO. He received the first-ever Bitcoin transaction, and he's been contributing to Bitcoin since before 0.1 was released.
MagicalTux got "free" VIP status for hosting the forum for a long time, too. I think that him plus Hal are the only free donator statuses I gave out. You'd have to do something pretty extraordinary to convince me to give out another free one.
I don't see any point in donating 5 BTC now and then 5 BTC later. You won't get Donator status until you've donated a total of at least 10 BTC. It'd be better for you to earn interest on the 5 BTC somewhere until you're ready to pay 10 BTC. The forum isn't in need of money.
Maybe they didn't donate 50 BTC but were gifted the VIP status because of their contribution to Bitcoin and the forum.
Right. I posted about this somewhere when I did it.
IIRC MagicalTux also got VIP without paying 50 BTC because he contributed significant resources in other ways.