Don't really think you'll find anything that will work well. The previous poster mentioned two possibilities (think Fuji have something similar too), but it's really kludges at the moment.
Think you're correct that the best option now (for image quality) is the Sony R1, but there are also prosumer models like Nikon 8800, Panasonic Fz30 etc that offers a really long zoom range if that's what you want, but at the cost of image quality, specially in difficult situations.
However, many people have been waiting years for a camera that will combine the image quality and interchangable lenses of a slr with LCD preview. Sony has shown (with the R1) that it's possible, even though it still has a fixed lens. With the Sony-Minolta deal this summer it would be pretty likely that Sony will come out with a model compatible with Minolta lenses fairly soon.
It would also be surprising if no other manufacturer don't follow up with a model that also have interchangable lenses. Btw, last time Sony came out with new sensor for the prosumer market (the 8mp sensor found in the 828 model) it took only months before all the major companies had competing models out.
This time it's probably not quite as easy as the sensor is a completely new design, and not an upgrade that will fit in existing models. In addition, it would be surprising if Canon used this sensor as it's clearly a direct competitor to their own cmos designs. It would also be surprising if Olympus started using a sensor that's larger than the one they use in their slrs. Still, there are Nikon and Minolta which both work closely with Sony, and of course a lot of other players like Pentax, Casio etc.
Could go on and on (even more), but the conclusion is that I'd be surprised if you don't see something even better suited to your needs than the R1 within 6 to 12 months.
Disclaimer: I don't have any inside info at all, so this is all based on educated guesses, not facts.