San Antonio Spur(ned):
PG: Jason Kidd
SG: Manu Ginobili
SF: Richard Hamilton
PF: Tim Duncan
C: Chris Kaman
I don't like Rip Hamilton as a small forward either. He is a very weak rebounder there and he'll struggle against physical / powerful small forwards defensively.
Chris Kaman will need to the play four with Duncan at center. Duncan no longer has the quickness required to play as a forward on a regular basis.
Kaman will have a few troublesome matchups there but he'll do a solid job on most non-perimeter based PFs. Back with the Clippers when Brand was still there, Kaman spent a fair bit of time defending top power forwards.
His defense has dropped off badly over the past few years but I think he'll improve here and be a solid defensive presence as a four (aside from the perimeter based matchups where he'll be a liability defensively). When he switches to the five while Duncan rests, he'll probably be below average defensively again although hopefully not as bad as he's been with the Clippers over the past few years.
Offensively, the Kaman and Duncan combo will regularly give you at least one matchup advantage in the post. When facing smaller PFs, Kaman's offensive efficiency in the post should increase considerably. More than enough floor spacing with Kaman's + Duncan's combined jump shooting ability too.
It should also receive a bump from playing with such wonderful passing guards + Duncan is an excellent passer + Rip is an above average passer ... and as a 3rd/4th option in the lineup, the decreased responsibility offensively (and hence decreased defensive attention from opposing teams) will also increase his efficiency. I think he can get back to being a 56-57% TS% scorer in this smaller role.
When playing against tall long PFs, like Pau Gasol or LaMarcus Aldridge, Kaman will likely see a drop off in efficiency though. More likely a 54-55% TS% scorer (as a 15ppg threat -- bigger decrease in larger scoring role).