At your price point and with tube equipment you're really limiting yourself in terms of options by looking for a 3-way speaker. I find speakers to be the most personal of all audio equipment choices, so I'd say focus on finding the right speaker for your system and tastes in your price range and forget about how many drivers and/or crossovers the things have. This will open up a world of possibilities, and I'd be surprised if several 2-way speakers didn't surpass what the 3-ways can do at this price point in terms of overall sound quality, and many will put out enough bass to keep even a head-banger fairly happy. I guess what I'm saying is quality over quantity when it comes to speakers.
That said, I'd echo the Vandersteen 2ce recommendation above although they can be a little on the polite side for some so obviously try before you buy. The Triangle Antals will also work very well with tubes and will certainly satisfy your need for more drivers. If you want to buy new, Axiom and Energy offer towers that are high on the drivers per dollar scale and have gotten some nice reviews, but I'm not sure how they'll work with tubes or, more specifically, your tube equipment. Best of luck.
Tim