Well, if you're on this forum you must be a little bit of a DIYer. I recommend building your own! There are several sites that sell ready-to-make kits, including pre-drilled housing, PCB, and all the parts you need. All you need is to paint it (or leave the enclosure plain) and solder! One of the greatest things is that these kits are in much smaller enclosures than most other effects, saving that precious floor space.
Build Your Own Clone (BYOC) offers a tube screamer kit, complete with all of the popular mods so you can choose what you want to do with it. Although it looks like right now they are coming out with a new TS+boost kit. They also have a Rat kit that has a switch enabling you to select 6 different clipping stages, including the original, higher gain, and asymmetrical clipping.
http://www.buildyourownclone.com/
There's also General Guitar Gadgets, which offers copies of classic effects as well.
http://www.generalguitargadgets.com/index.php
I can't recommend either of these guys highly enough. You can build your own boutique effects at a fraction of the price!