I made 3 of these a few years ago, little mini ones. I used the same lock tight container like that link you posted but mines was much taller and thinner. I used Rio pumps. Works good.
I remembered buying my air tight seal container at Wal Mart, They have different sizes incase you want to throw in a strong powerhead. Except mines were the thin tall version. The dimensions were something along the line of 5''LX15''Hx5''W. I used a Mini Rio powerhead, which was mount on the flat lid underside with the tip of the powerhead facing outside ontop. I used a series of automotive glue that once harden turns into hard plastic. I also cut the power cord and drilled a hole on the lid for it to came through. I then solder the connection up and glued around that hole also. From there on out, it was just the matter of hooking up your inlet and outlet hose to the tank and plugging it in.Well, it is settled, eheim isn't getting any more of my money. I would never have thought of this, thanks for the post.
How tight is that seal though? Jagged, have u ever had any problems with leaks over time with these setups?
Sorry to be off topic and such but:You can pick up a cheap filter off ebay for the same amount ...