Okay, I think I really bricked this phone.
I was using JH2, flashed to JM3 (i9000) + i897 kernel and it was working just fine until I decided to try "modaco's JP3" because of the "unrestricted bootloader" but I didn't like it then I flashed JH3... I flashed it and before the AT&T world phone screen now I see the GT-i9000 screen as well but I was able to boot normally.
When things went bad:
I decided to update my kernel to the 1.2oc version so typed "adb reboot download <enter>" but forgot to open odin first... I just ignored and opened odin.
Odin started but would not go past "flashing zImage" or something like that and there was no blue bar on my download screen.
In a very dumb moment I decided to pull the battery and do the proper way: "odin THEN download mode"
I was used to get the phone - ! - computer screen then download mode but this time I'm stuck on that screen. It flashes 2 times but no download mode.
My guess is the i9000 rom changed the sequence to enter the download mode and due to the lack of a d-pad I will never be able to get it. I will need to get a new phone...
In your case, I would pull the battery, plug in the USB cable, hold the down volume button and then put the battery back in, or some variation of that.
Hope that works for you.