why and when did yoropiko come into existence? i mean is it a rmc line or a separate brand?

Yoropiko's belongs under same roof as RMC. I've understood that it's a separate brand, but as said belongs under same corporate umbrella as RMC. It's kind of what Lexus is to Toyota, heh. Yoropiko's simply put, Martin's premium line of denim (as if RMC wasn't premium enough, heh).
Was it that the first Yoropiko jeans was the Yoropiko x RMC x Santastic pair of jeans? Or was it more of an unofficial Yoropiko design?

Yeah, Tony has explained that very well with the synergy between Lexus and Toyota, couldnt have put it better myself. I think Yoropiko for Martin was a way for him to expand his ideas without having to conform to the RMC mold of just Embroidered pockets. Certainly the construction is at a higher level than even RMC given the whole of the Jeans is Selvedge throughout as apposed to just down the leg and of course the Buttons are a unique feature. I think it has also allowed Martin to experiment with innovative collaberations as well.
I would agree that the Santastic x Yoropiko x RMC Jeans were in effect the start of the Yoropiko brand, however that wasnt the first time we saw the Yoropiko logo doll in one of Martins designs, the Buddha Gutta RMC had it on one of its rear pockets.

Does anybody know where to get the custom buttons and how much would they be?

If we're talking about the official custom buttons in silver or with jewels. I guess the best place to ask would be to contact Paul at rmcsales about that. Not sure if togged has any of the separately sold buttons or if they're even available outside HK/Taiwan axle.

yes Paul does carry the buttons but they cost ALOT!

No doubt, heh. I checked out the silver buttons at seleven and they were something like 1000 HKD. If my memory serves me right that is. Since the basic extra buttons are not cheap at all, I can just imagine how much the jeweled buttons are, heh.

i'm guessing probably $10000usd for the diamond buttons lol. Being how the diamonds are all very high quality and amount of work to make the buttons.. i expect it to be around that much.

I remember checking the prices a couple of years ago regarding the spare button sets, I think a full set of Gold buttons is approx £70 a set, the multicoloured bejeweled set ( sapphires, emeralds, rubies ) that can be seen at the top of the form home page are about £1000 a set and the fully bejeweled Diamond set a staggering £11,000! I think you could easily own a pair of the most expensive jeans in the world with just this set of Buttons attatched to your Yoropikos

Wow!! there goes my idea of getting some