Thought I'd chime in w/ a suggestion from something I owned for a while. It doesn't actually use tubes though: Empirical Labs Distressor. It's an aggressive-sounding (colorful) boutique compressor w/ a harmonics generator in it for 2nd order distortion (tube) or 3rd order (tape saturation.) Sounds fantastic. Expensive as hell though, hence "something I owned" as opposed to "own"... sold it to fund a Future Retro XS.
Check it out though if you're interested in an alternative to tubes that sounds just as good.
