I've never tried, but I would be amazed if it could. My captivate could play 720p video usually, my iPad 1 couldn't even do that while I had it. These aren't that much slower than the Focus S in processing power, so I wouldn't expect it to make the jump to 1080p.
Heck, the dual core snapdragons at the same clockspeed haven't proved themselves able to handle 1080p. Right now, the only mobile chips I know will play 1080p are samsung's Exynos chips, and Apple's A5. I think the later TI chips can, and I assume Tegra 3's can (T2's cannot, but they have no hardware video decoder at all, unlike the T3).
As for the Focus playing 1080p videos...one can only assume something happened over sync such as downsizing them. 1080p is in the range of upper dual cores/quad cores right now. A 3 year old chip isn't going to cut it.