I was looking at this a while back, and one setup I found was
Feat: Half-Dragon Form (Dragons of Eberron)
Steel Dragon Alternate Form: Flind (gnoll, humanoid)
Flind: +6 Str, +2 Dex, +4 Con
Half-Dragon: +8 Str, +2 Con
Basically giving you physical scores of
24 Str, 12 Dex, 16 Con
Compared to Polymorph or Draconic Polymorph, it's not ridiculous, but it at least seems to be a reasonable humanoid combat form. Not sure if you'd gain proficiency with the flind bar in the process.