The Wizard Evolved and Wizard's Apprentice Evolved from Mark Bugs are basically the same mod, with one made of implant grade titanium, and the other made from Stainless Steel. The Wizard's Apprentice Evolved (the cheaper of the two) is still a whopping $342.68 (By current exchange rates) and the Wizard Evolved is quite a bit higher than that... They do offer a 1 year warranty, but the manufacturer is in Romania. The Wizard is currently out of stock, but the Wizard's Apprentice is available. These are beautifully crafted mods... More articulate craftsmanship, IMO, than the ProVari. I mean, these are NICE... With a price tag that matches that fine grade of work... These are VW ONLY devices (No VV Option)
Products
The Semovar by SvoëMesto (Same folks who make the Kayfun line of RBA's) is at a more reasonable price range. It's made in Germany by a Russian company, so who knows where you would send it for warranty work. It is also protected by a one year warranty. It's a well crafted stainless steel device with a modular design... So, if you accidently crush a battery tube or something silly, you can replace just the battery tube, or just the top cap, or just the control head, etc... I don't know if it's as heavy gauge a steel as the ProVari, but it certainly looks to be a quality piece, and offers a real alternative to a ProVari for those folks who also want VW. Not in stock right now, but for $215 it would be worth waiting for, IMO. Something neat these guys do is make several different top caps for the device to match up with a variety of different toppers. They even make an adapter to combine a Semovar with a Kayfun to make a Hybrid regulated mod. Cool stuff...
Semovar Mod - SvoëMesto - Variable Voltage - Devices
This should at least let you know where to buy them when your research is complete!