On paper at least, the basic specification of the K10D doesn't seem that different from the mainstream Sony offerings.
Regarding the high iso noise, if you haven't already, look at the cameralabs review
which gives side by side examples against a Canon 450D. While there is a difference, how much and if it is acceptable will be down to the shooter. Whichever camera you have (of APS-C sensor size) will have reduced quality at higher ISO levels. While there are small differences between them, personally I don't think they're that significant.
To my personal preferences, I'm happy using up to ISO400 routinely on the higher resolution A350. If I'm in control of the environment, I'd try to keep within that zone. I only go higher if motion blur becomes a bigger problem than image noise, such as in low light situations at longer focal lengths.
To stick clearly in the semi-pro category, how about the Canon 40D? This gets you the live view although not the tilting screen.