You'll probably be going hardtail. First, quality full suspensions generally cost more than $1000, and there aren't a ton of single speed full suspension bikes out there because you generally have to play with chain tensioners so the chain doesn't go slack when the rear suspension is working. You might be able to buy a Giant Yukon FX and do a conversion, but by the time you have the bike and stuff to singlespeed it, you're over $1000. There should be plenty of hardtail singlespeeds at your pricepoint though. Any in particular you're looking at?