Here's a list of camera / lens-specific update blogs on Digital Photography Notes.

Canon

1. Canon XSi / 450D (2008)
2. Canon 40D (2007)
3. Canon G9 (2007)
4. Canon XTi / 400D (2006)
5. Canon 5D (2005)

Nikon

1. Nikon D60 (2008)
2. Nikon D3 (2007)
3. Nikon D300 (2007)
4. Nikon D40X (2007)
5. Nikon D80 (2006)
6. Nikon D200 (2005)
7. Nikon 70-200mm f/2.8G ED-IF AF-S VR (2002)

Olympus

1. Olympus SP-570 (2008)
2. Olympus E-3 (2007)

Panasonic

1. Panasonic FZ18 (2007)

Pentax

1. Pentax W60 (2008)
2. Pentax 55-300mm(2008)
3. Pentax K20D (2008)
4. Pentax K10D (2006)

Ricoh

1. Ricoh GX-200 (2008)