Is backward compatibility a big part of your purchase?
With the quality of games for the PS3 (including the very reasonably priced PSN downloadable games) I have had no reason to play PS2 games. I think I tested the backward compatibility once and my original PS2 is gathering dust.
If it is a real need for you, my advice would be find the best deal being offered for a new PS3 and PS2 and buy both. It will still come out cheeper than trying to find a 60gb model from what I can see. (Not to mention the fact that you will be covered by warranty on new consoles vs second hand).
The other advantage to this is your wife can be playing the PS2, leaving the PS3 free for you
Caution: I can make "brave" claims like the one above through the protection of this forum. I don't have to sell this idea to your wife, you do!
I take no responsibility to any disruption of your marital bliss or loss of "special cuddles" if you attempt the above suggestion.
If I tried to apply that last suggestion in my household I would quickly end up with a PS2 lodged somewhere the design engineers never intended for it to go (other wise it would not have come with so many corners

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Console purchases can be a dangerous undertaking if you do not have the total support of "she who must be obeyed".
Good luck my friend and I hope to see you online with your new PS3 soon (hopefully with you sitting comfortably

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