You're right. People with longer arms are not able to bench as easily as those with shorter arms. I'm not sure about how Shaq was only able to bench 150 when he came in though. That sounds like way too low of a figure.
Goodness I hope so... I did that weight in 7th grade football. I was hittin' a thousand in 9th. Of course o-line guys need more leg power than b-ballers, I'm sure. We talkin' Shaq here right? Not his wife? 150 pound bench? Wuss.
There was a story in one of the Toronto papers last year about some of the younger Raptors and their conditioning. Apparently several of the young frontcourt guys (and Jerome Williams) were seeing who could bench more and no one could get past 280. Well along comes Vince Carter and does it without so much as a grunt. Part of the reason he doesn't get calls is because he is actually pretty strong for a guard and can absorb more contact than guys like Iverson, Rip Hamilton, Ray Allen, etc... There's a lot of guards who are pretty strong. Any athlete over 6' and 220lbs should be able to bench atleast their own weight, let alone a professional athlete. If I was a GM I would implement a 300 lb bench "target" for any frontcourt player. Thin guys would have trouble with that but any self respecting "big man" who's beyond his rookie contract - say like Cato or Taylor - should shoot for a minimum of 300 lbs bench and 600 lbs leg press.