Thanks, I'm going to ask the UK distributor where I bought it from.
It was originally good for s939 Athlon X2 4800+ which I think was circa 95W TDP, so I'm thinking it should be fine with even the i7 860/870 at stock clocks (provided the airflow is good, that Athlon 4800+ required wasn't recommended for passive cooling.) The lesser i3/i5s are lower TDP anyway, and I see Intel's website is now showing the S versions of i5/i7 as available, so I think it really is only a question of finding a bracket.