No, Microsoft is a software company, not a hardware company.
The Kindle works because it only needs to do one thing (read books) so it only needs an e-ink display and low-power components which enable it to have a small profile and thin factor.
A suitable tabletpc (with today's tech) would be at least 2cm thick and have enough battery for 5 hours reading, tops. Large-scale OLED displays aren't due for another few years and we've reached the peak in the energy density of batteries (until those 'air' batteries come out in 5-6 years time)