Managed to get working a stripped down version of my code on LPC1769 Xpresso board with OV7670 FIFO module. Since I’m handling the IO and interrupts using macros, was not that hard. With serial port running @ 921.6 kbps I am able to reach around 4 fps (@ 160 x 120) using Processing to display the serial stream. I should be able to go even higher, however, I did use a serial communication protocol that is requesting a new frame only after previous one was displayed which adds some delays too.
There is no processing or colour handling done, but that should not be an issue I guess.