That's pretty much unobtainable for a couple of reasons.

The OMAP2 parts are BGA (ball grid array). Unsoldering and soldering a different part in takes some pretty specialized equipment.

If you could overcome this problem, then you would need a pin compatible part. Veiwing http://en.wikipedia.org/wiki/Texas_Instruments_OMAP shows this isn't something available from TI at this point in time.

Frank