I'd find such a product potentially interesting, but I'd be careful about dropping the power specs too far... I realize that you want to meet a price point, but if the power output is too low, you limit your potential market dramatically.
For me, personally, I might consider such a unit for a bedroom system. A lot of 2 way monitors that I'd consider for a bedroom system, however, are around 85-86 dB, and 50W/channel seems a bit low for that.
Don't forget that there are a lot of receivers out there now that would come in between $200 and $500 with 5, 6 or even 7 amps at 75-100W/channel. They might not compete with your product in terms of outright audio quality, but spend the $500 to $800 savings on mods, and you might get close enough that the greater available power and extra features would tip the balance, especially if you can bi-amp them.
The other end of the spectrum includes the current set of integrated amps already on the market. Your proposed price point makes quite a statement when competing against them, but 100W/channel seems to be the popular power point for many integrateds.
One other point - a remote with mute and volume are a must, and input selection highly desirable. If you
really/i] want to tempt me, add a USB input port! 