I've got the BLKR975~ version. It does overclock, but if the settings don't work out you've got to reset the BIOS settings with a two stage reset/power up process - not OC friendly at all.
A small correction, my Intel motherboard currently has a D940, the D820 is on a Gigabyte 945G based motherboard I use for rendering, I checked last night. The D820 only got about 3.7GHz with a Vcore of about 1.5V.
I'd agree on other Intel motherboards, well the few I've used.http://www.anandtech.com/mb/showdoc.aspx?i=2681&p=4
I just saw the "Grand County" at the suppliers and the price looked good (about USD100) so I was just suggesting the OP look at it since it was the only Pentium 4 D motherboard I'd seen that supports DDR1 - I've stayed away from VIA/SIS as they've seldom performed well as a NLE station (video editing where HDD performance is key), not that anything with an ATI south bridge would be much better.