Well I saw you mention that you want a Red 1. Great choice, but seems a bit out of your stated price range.
Are you at a serious loss for more pres, or would you just like some more to "fill things up" The reason I ask, is because if you're not desperate for inputs, I would recommend always taking quality over quantity.
There's a ton of amazing single channel pres in the thousand dollar range, and a number of good dual channel's. Off the top of my head I can't think of any quad pres that would be a noticable step up from what you've got going on now. So I'll start with a couple of best case scenarios and work our way down.
1 Channel. My personall choice would without a doubt be a Great River ME-1NV. It's a tad over $1000, but you should be able to find one used for around a grand. It's a phenomenal pre that can really make you understand why so many people just use a 57 on a guitar amp. Can go from clean to dirty with a turn off a knob, and sounds good on everything.
Daking mic pre one. Brilliant little pre for well under budget. Probably run about $750-$800. A little brighter and smoother than the great river, with wonderful creamy tone. Not quite as versitile though. Awesome metering. For those who care about such things.
You could buy a lunchbox and take your pick of a 500 frame pre for a bit under $1000. Infinite range of flavours, and very expandable. Keeps you wanting more. Kind of like crack.
Grace m101. Don't have any personal experience with this one, but it's supposed to be very smooth and clean. Millenia ish, without the Mileeniaish price.
Presonus Eureka. Decent little channel strip with a usable comp and EQ. Can be had for about the same price as the m101. I think Tim might still have a pair of these.
2 channel
AEA the Ribbon Mic Pre. No phantom so can't use it with condensers, but clean headroom for days! No real experience with this one either, but the specs and reviews are fantastic. Could always get a seperate phantom supply.
ART MPA gold. Way under budget, but a very usable stereo preamp. Maybe this is what you already have? Nothing to be ashamed of. Could also go with the digital option if you want to use up those digital ins.
4 or more
M-Audio Octane ok preamps with ok converters. 8 channels though. If you're going to go this route, I'd say save some money and get the ADA-8000. Build quality is not quite as good, but sound is similar.
Mackie Onyx 800r. Again the 8 channel with converters deal. Better the M-Audio or Behrry, but $800 better? probably not.
Sytek has a 4 channel somewhere in that price range, but I don't really know anything about it. I can't think of any other 4 channels in that range. It seems to mostly go from 2 channels to 8 channels for some reason. You could always get a DIY kit or something like that. Seventh Circle Audio, if you're into that.
Daking 4 channel for about $2000 is one of the best value multi pres out there
Anyways, there's a dozen or so options that I have at least a little experience with. There's about a billion more options. Did that help, or just muddy that waters?