Best Pre-amp for Bi-amping?

If I want to bi-amp my speakers (a dream I've had), I assume the pre-amp should have two outputs for each channel. My CJ PV12 only has one set of outputs for the amp. If I was to upgrade the pre-amp which ones are best suited for bi-amping?
I have been thinking about this recently. One thing to consider, in addition to the other excellent suggestions, is a preamp with regular and "bypass" outputs. For example, the Adcom GFA 555 II has "tone bypass" outputs that could be connected to the bass amplifier, and regular outputs that you could connect to the treble amps, but you could turn the bass down on these (to not amplify the unwanted power-hungry bass frequencies) and to level-match. This in no way would affect the other outputs. Very interesting. This to me is similar to having an active x-over, but without the hassle, and is a more elegant solution. The down side is that only lower quality preamps have such tone controls and "bypass" outputs. You would need to get an adcom or perhaps a Hafler or luxman or parasound. Hey, its just and idea worth considering. It appears to be the most economical and elegant solution, you could level match by using the tone controls and your single volume control would control all 4 outputs.
Oooops. I meant the GFP 555 II, of course!
The Marsh Sound Design's P2000 SS preamp has four outputs for the very reason that you mention. While i'm not saying that this could replace your preamp, Marsh does make a hybrid tube preamp that "might" have four outputs also. Just a thought. Sean
Levinson 32 has two balanced (XLR) and two unbalanced (RCA) per channel. I don't know rest of your stuff, but it is the best I've ever heard in my system (all-ML & B&W).
I have a conrad-johnson pv10a. I biamp using mogami rca y adapters available for $10 from my local audio store. I emailed c-j and they said this should work fine. I probably lose some resolution, but for my system it seems to work ok. It is a cheap solution to try and see if you like it. Paul