I did post a few pictures in this msg
http://ecorenovator.org/forum/35514-post433.html
Obviously there are several possible designs, depending on the amount of space you have and what fans you are using.
I am still using the HRV pictured in that message although now I would build it a bit different. The fans used there are AC-fans which use more electricity than DC fans (About 35W together in the lowest setting where DC-fans would use below 10W (a difference of 50,- a year on electricity)) and over time these fans started to make more noise. Alas it appears better fans are rather expensive.