Sovos hubs suck, from my experience. I've had them on my '94 Cannondale M300 and my wife's '94 Trek 700 and they lasted less than a year of normal riding. The hub cones are of a very soft material and they get pitted very easily. Steer clear of these!
You're better off getting a Van Dessel rearwheel or getting a rear wheel built up for you for about 80 dollars. The front wheel isn't as important (in terms of functionality towards fixed/ss) and thus you can get a regular decent front wheel from 30 - 80 bucks (online, used or from your LBS). The rear is worth investing in and you may well do with putting most of your money there (in quality) and later on when the budget fits, get a matching front wheel. If you already have an existing front wheel use that in the meantime.