The first one is not a rumor but rather an update: Sony A550 DSLR officially went on sale yesterday (it was initially delayed).
A dpreview member did some investigation of the Sony RAW files EXIF data which contains codes for the different camera models. The sequencing of the numbers suggests that Sony may be working on six new camera models:
2 = DSC-R1
256 = DSLR-A100
257 = DSLR-A900
258 = DSLR-A700
259 = DSLR-A200
260 = DSLR-A350
261 = DSLR-A300
???
263 = DSLR-A380
264 = DSLR-A330
265 = DSLR-A230
???
???
???
269 = DSLR-A850
???
???
[??? = DSLR-A500 Files not examined]
273 = DSLR-A550
There are already rumors online for a new Sony camera being released on November 18, 2009. The camera is expected to be a competition of the Panasonic GH1 and should have the new Exmor R sensor and full HD video recording. Sony mirrorless camera has been rumored for a while - see this post and this report.