this thread seems quite pointless. If you don't want to mic an amp, then use a GUITAR preamp. If you want Fender tones, then use a Fender preamp (or preamp out from the amp), if you want Marshall tones, use a Marshall preamp, etc.
However, this is my advice. If you want to go direct, Use either a modeller (vox tonelab, POD) or software (Guitar Rig). I guarantee the "fender" or "Marshall" settings will sound much better and more authentic than the preamp outs on the actual Fender or Marshall amp. Remember, the modellers model not just the preamp, but the power amp as well (which is where half your tone comes from). If you just use an actual guitar preamp, you'll probably need a speaker emulator, etc.
Bottom line. Use a modeller/software, or mic an amp. Don't use a DI. Don't use the preamp out of an actual guitar amp.