I'm not intimately familiar with Trek--what's the 1.2 got on it?

To get the weight savings and the stiffness when standing, (I'm guessing) you may want to look at a more race-oriented frame, especially since you mentioned you don't have the control you like on the Ruby. (Though go ahead and test out a few more to see if it's the "endurance" geometry that you don't like, or just the Ruby.)

Do you need WSD?

Hmm...as to whether or not you buy a full-Ultegra bike to begin with, or buy a 105-equipped bike and upgrade later, or just buy some nicer wheels...While it's cheaper to buy what you want to begin with (learned it the hard way!), I've heard that there's not that big a difference between 105 and Ultegra as far as feel goes. Ultegra's a little lighter and shinier, but 105 is quite solid. Here's what I think...Buy a 105-equipped bike, then buy yourself some nicer wheels than what it comes with. Start saving. You might be able to swap stuff out piece-meal. DBF worked at a bike shop for a while, and he says check when the new componentry comes out, then see if you can get a deal on the previous year's. (It's how he managed to upgrade his OCR3 to Ultegra.)

I'm struggling with this too--I'm in love with an Ultegra-equipped carbon bike, but there's no way I could afford it.